Burn rate and barrel length

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Burn rate and barrel length #6177773 02/10/16 07:09 PM
Joined: Mar 2012 Posts: 3,809 C Cleric OP Extreme Tracker
OP Cleric Extreme Tracker C Joined: Mar 2012 Posts: 3,809	Question... If you have a shorter barrel does the saying of xx fps per inch go down if you select a faster burning powder. So if I had a handful of powders that could get approx the same velocity. Would the faster burning one have a higher chance of getting that velocity out of a shorter barrel? Thanks

Re: Burn rate and barrel length [Re: Cleric] #6177783 02/10/16 07:22 PM
Joined: Nov 2007 Posts: 9,521 Wise Co. R RiverRider THF Trophy Hunter
RiverRider THF Trophy Hunter R Joined: Nov 2007 Posts: 9,521 Wise Co.	Nope. "Arguing with you always makes me thirsty." -Augustus McRae

Re: Burn rate and barrel length [Re: Cleric] #6177787 02/10/16 07:26 PM
Joined: Sep 2009 Posts: 18,951 Lewisville, TX C ChadTRG42 THF Celebrity
ChadTRG42 THF Celebrity C Joined: Sep 2009 Posts: 18,951 Lewisville, TX	Yes. It's a close trade off. Take a 308 Win. Varget is a great 308 powder for the 168-178 grain weight bullets. If you were to run the Varget in a longer barrel (26"), you will get more speed than a faster burning powder, like 4895. And you will get a complete powder burn longer down the barrel. Opposite goes for the shorter barrel. The faster burning powder will reach pressure sooner, and have a more complete burn in a shorter length time and barrel length. So, you will get slightly more speed in a shorter barrel with a faster powder than you will with a slower powder. This is why I recommend a faster burning powder for your shorter barrels. Also, if it's a gas gun, the gas port is about 9" to 11" away from the chamber. A slower burning powder will have much more port pressure than a faster burning powder will, since the faster burning powder will reach peak pressure much sooner, and bleed off pressure more quickly, and reduce port pressures. Something in the 8208 and 4895 area is about ideal for a gas gun with an 18" to 20" barrel length. But Varget does perform excellent in an Armalite AR-10T with a 175 SMK, and gets great speed. Custom and Precision Ammunition!! https://DallasReloads.com/ Type 01 and Type 06 FFL

Re: Burn rate and barrel length [Re: Cleric] #6177793 02/10/16 07:33 PM
Joined: Nov 2007 Posts: 9,521 Wise Co. R RiverRider THF Trophy Hunter
RiverRider THF Trophy Hunter R Joined: Nov 2007 Posts: 9,521 Wise Co.	I guess that deserves an explanation. Using the larger cartridges and the slowest burning powders, the powder is as consumed as it can be by the time the bullet has moved about ten inches. With more typical cartridges like .30-06, all the powder that is going to burn will do so in about four inches of bullet travel. Some cartridge and powder combinations won't achieve 100% burn no matter what the barrel length. "Arguing with you always makes me thirsty." -Augustus McRae

Re: Burn rate and barrel length [Re: Cleric] #6177795 02/10/16 07:33 PM
Joined: Mar 2012 Posts: 3,809 C Cleric OP Extreme Tracker
OP Cleric Extreme Tracker C Joined: Mar 2012 Posts: 3,809	So for a 7mm-08 with an 18in barrel what type of powder speed am I looking for? Ideally I could use something in the 162 grain area

Re: Burn rate and barrel length [Re: Cleric] #6177796 02/10/16 07:35 PM
Joined: Nov 2007 Posts: 9,521 Wise Co. R RiverRider THF Trophy Hunter
RiverRider THF Trophy Hunter R Joined: Nov 2007 Posts: 9,521 Wise Co.	Not so Chad. Powder burn ceases when pressure falls to a certain point. "Arguing with you always makes me thirsty." -Augustus McRae

Re: Burn rate and barrel length [Re: RiverRider] #6177798 02/10/16 07:40 PM
Joined: Sep 2009 Posts: 18,951 Lewisville, TX C ChadTRG42 THF Celebrity
ChadTRG42 THF Celebrity C Joined: Sep 2009 Posts: 18,951 Lewisville, TX	Originally Posted By: RiverRider Not so Chad. Powder burn ceases when pressure falls to a certain point. At what point is that? Custom and Precision Ammunition!! https://DallasReloads.com/ Type 01 and Type 06 FFL

Re: Burn rate and barrel length [Re: Cleric] #6177814 02/10/16 07:55 PM
Joined: Nov 2007 Posts: 9,521 Wise Co. R RiverRider THF Trophy Hunter
RiverRider THF Trophy Hunter R Joined: Nov 2007 Posts: 9,521 Wise Co.	I wouldn't know exactly. What I DO know is that sometimes you'll have to push a load harder with a given powder to achieve 100% burn. Pressure falls rapidly as the bullet moves down the bore. Since modern smokeless is progressive burning, the burn requires high pressure be maintained long enough to complete. I picture that as a surfer trying to stay up high on the face of a wave to get a good ride. Higher velocity with slower burning powders has more to do with the amount of gas generated than how long the powder burns. The burn rate only determines the speed at which that volume of gas is generated. "Arguing with you always makes me thirsty." -Augustus McRae

Re: Burn rate and barrel length [Re: Cleric] #6177824 02/10/16 08:04 PM
Joined: Sep 2009 Posts: 18,951 Lewisville, TX C ChadTRG42 THF Celebrity
ChadTRG42 THF Celebrity C Joined: Sep 2009 Posts: 18,951 Lewisville, TX	Yeah, I'm scratching my head right now. I'm running some numbers in QuickLoad, and they are not showing me what I'm thinking. But the more pressure I have, the more complete burn is achieved. I know that from playing with subsonic loads. Custom and Precision Ammunition!! https://DallasReloads.com/ Type 01 and Type 06 FFL

Re: Burn rate and barrel length [Re: Cleric] #6177842 02/10/16 08:12 PM
Joined: Nov 2007 Posts: 9,521 Wise Co. R RiverRider THF Trophy Hunter
RiverRider THF Trophy Hunter R Joined: Nov 2007 Posts: 9,521 Wise Co.	Exactly. I've been paying more attention to burn percentages lately, and one of the powders I was interested in showed about a 97% burn, IIRC. With an increased charge and the resulting higher pressure peak, consumption jumped to 100%. Not to derail the OP...but, I got to thinking about it and it stands to reason that if you can get consistently high enough pressure to always achieve 100% burn, then all that carefully metered powder will yield the most consistent volume of gas, and therefore the most consistent velocities. Kinda falls together nicely, doesn't it? "Arguing with you always makes me thirsty." -Augustus McRae

Re: Burn rate and barrel length [Re: Cleric] #6177856 02/10/16 08:22 PM
Joined: Nov 2007 Posts: 9,521 Wise Co. R RiverRider THF Trophy Hunter
RiverRider THF Trophy Hunter R Joined: Nov 2007 Posts: 9,521 Wise Co.	Chad, since you are running QL, try running a powder profile on something like .308 and set barrel length to 18 inches, then run it again with a 26-inch barrel. You'll see that the results show a very consistent order of powders sorted by velocity. "Arguing with you always makes me thirsty." -Augustus McRae

Re: Burn rate and barrel length [Re: Cleric] #6178038 02/10/16 10:31 PM

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RiverRider

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For the OP...

First, with a 26-inch barrel:

Code:

Cartridge          : 7 mm-08 Rem.
Bullet             : .284, 162, Hornady A-MAX 28402
Useable Case Capaci: 45.033 grain H2O = 2.924 cm�
Cartridge O.A.L. L6: 2.800 inch = 71.12 mm
Barrel Length      : 26.0 inch = 660.4 mm

Predicted Data for Indicated Charges of the Following Powders.
Matching Maximum Pressure: 61641 psi, or 425 MPa
or a maximum loading ratio or filling of 106 %
These calculations refer to your specified settings in QuickLOAD 'Cartridge Dimensions' window.
C A U T I O N : any load listed can result in a powder charge that falls below minimum suggested
loads or exceeds maximum suggested loads as presented in current handloading manuals. Understand
that all of the listed powders can be unsuitable for the given combination of cartridge, bullet
and gun. Actual load order can vary, depending upon lot-to-lot powder and component variations.
USE ONLY FOR COMPARISON !

58 loads produced a Loading Ratio below user-defined minimum of 86%. These powders have been skipped.
Powder type          Filling/Loading Ratio  Charge    Charge   Vel. Prop.Burnt P max  P muzz  B_Time
                                      %     Grains    Gramm   fps     %       psi     psi    ms
---------------------------------  -----------------------------------------------------------------
Alliant Reloder-17                 102.9     44.8     2.90    2840   100.0    61641    7866   1.227  
Winchester 760                     101.7     44.7     2.89    2793    98.9    61641    8021   1.244  
Hodgdon H414                       101.7     44.7     2.89    2793    98.9    61641    8021   1.244  
Vihtavuori N550                    104.2     44.2     2.86    2786    99.9    61641    7850   1.252  
Accurate 4350                      106.0     44.0     2.85    2765    99.9    60070    7679   1.274  
Hodgdon CFE223                      91.6     42.3     2.74    2758   100.0    61641    7321   1.252  
Ramshot Big Game                    97.0     42.9     2.78    2758   100.0    61641    7336   1.251  
Ramshot Hunter                     106.0     45.4     2.94    2757    99.1    58160    7980   1.269  
Norma 204                          106.0     45.4     2.94    2756    97.1    61240    7933   1.245  
Norma URP                          106.0     43.5     2.82    2753    99.9    59065    7691   1.269  
IMR 4895                            96.5     40.1     2.60    2749   100.0    61641    7335   1.262  
Alliant Reloder-15                  97.3     40.4     2.62    2740   100.0    61641    7309   1.263  
Norma 203B                          97.8     40.6     2.63    2739   100.0    61641    7252   1.264  
Hodgdon BL-C2                       92.0     41.7     2.70    2736   100.0    61641    7168   1.265  
Norma 203 old                       99.4     41.7     2.70    2734   100.0    61641    7147   1.273  
Hodgdon H380                        98.6     41.8     2.71    2732    99.8    61641    7421   1.266  
Winchester 748                      89.5     40.0     2.59    2724   100.0    61641    6875   1.260  
Ramshot Wild Boar                   92.3     40.9     2.65    2724   100.0    61641    7145   1.261  
IMR 4320                            99.2     40.5     2.63    2721   100.0    61641    7030   1.250  
Hodgdon H4895                       93.8     38.9     2.52    2721   100.0    61641    7064   1.266  
Ramshot TAC                         92.1     41.2     2.67    2701    99.6    61641    7244   1.264  
Hodgdon VARGET                      99.8     40.1     2.60    2701   100.0    61641    7055   1.259  
IMR 4007 SSC                       100.1     42.1     2.73    2700    98.3    61641    7401   1.268  
IMR 3031                            96.9     37.6     2.44    2700   100.0    61641    6508   1.269  
IMR 4350                           106.0     43.8     2.84    2699    98.1    59794    7464   1.270  
Accurate 2520                       92.1     40.3     2.61    2698   100.0    61641    6672   1.280  
Accurate 4064                       99.2     40.3     2.61    2697   100.0    61641    6670   1.297  
IMR 4064                           100.5     39.4     2.55    2691   100.0    61641    6888   1.264  
Vihtavuori N530                     90.5     37.8     2.45    2689   100.0    61641    6757   1.267  
Alliant Reloder-26                 106.0     47.3     3.07    2683    98.6    46294    8635   1.379
IMR 8208 XBR                        92.5     38.4     2.49    2682   100.0    61641    6685   1.267  
Norma 201                           95.2     38.7     2.51    2682   100.0    61641    6750   1.281  
Vihtavuori N540                     96.9     40.7     2.63    2680   100.0    61641    6692   1.273  
Norma 202                           94.6     38.6     2.50    2674   100.0    61641    6529   1.276  
Ramshot X-Terminator                89.8     39.8     2.58    2674   100.0    61641    6788   1.270

Then, with an 18-inch barrel:

Code:

Cartridge          : 7 mm-08 Rem.
Bullet             : .284, 162, Hornady A-MAX 28402
Useable Case Capaci: 45.033 grain H2O = 2.924 cm�
Cartridge O.A.L. L6: 2.800 inch = 71.12 mm
Barrel Length      : 18.0 inch = 457.2 mm

Predicted Data for Indicated Charges of the Following Powders.
Matching Maximum Pressure: 61641 psi, or 425 MPa
or a maximum loading ratio or filling of 106 %
These calculations refer to your specified settings in QuickLOAD 'Cartridge Dimensions' window.
C A U T I O N : any load listed can result in a powder charge that falls below minimum suggested
loads or exceeds maximum suggested loads as presented in current handloading manuals. Understand
that all of the listed powders can be unsuitable for the given combination of cartridge, bullet
and gun. Actual load order can vary, depending upon lot-to-lot powder and component variations.
USE ONLY FOR COMPARISON !

58 loads produced a Loading Ratio below user-defined minimum of 86%. These powders have been skipped.
Powder type          Filling/Loading Ratio  Charge    Charge   Vel. Prop.Burnt P max  P muzz  B_Time
                                      %     Grains    Gramm   fps     %       psi     psi    ms
---------------------------------  -----------------------------------------------------------------
Alliant Reloder-17                 102.9     44.8     2.90    2631    99.9    61641   12425   0.984  
Winchester 760                     101.7     44.7     2.89    2580    96.8    61641   12326   0.996  
Hodgdon H414                       101.7     44.7     2.89    2580    96.8    61641   12326   0.996  
Vihtavuori N550                    104.2     44.2     2.86    2576    98.9    61641   12169   1.004  
Hodgdon CFE223                      91.6     42.3     2.74    2558    99.8    61641   11520   1.001  
Ramshot Big Game                    97.0     42.9     2.78    2558    99.6    61641   11543   1.000  
Accurate 4350                      106.0     44.0     2.85    2557    98.8    60070   12004   1.024  
IMR 4895                            96.5     40.1     2.60    2549    99.7    61641   11522   1.011  
Norma URP                          106.0     43.5     2.82    2545    98.7    59065   11936   1.019  
Norma 204                          106.0     45.4     2.94    2544    94.3    61240   12018   0.994  
Ramshot Hunter                     106.0     45.4     2.94    2542    97.0    58160   12217   1.019  
Alliant Reloder-15                  97.3     40.4     2.62    2540    99.5    61641   11453   1.011  
Norma 203B                          97.8     40.6     2.63    2540    99.7    61641   11392   1.012  
Hodgdon BL-C2                       92.0     41.7     2.70    2539   100.0    61641   11267   1.013  
Norma 203 old                       99.4     41.7     2.70    2538    99.9    61641   11274   1.021  
Winchester 748                      89.5     40.0     2.59    2535   100.0    61641   10869   1.007  
Hodgdon H380                        98.6     41.8     2.71    2530    98.7    61641   11507   1.014  
IMR 4320                            99.2     40.5     2.63    2527    99.6    61641   11045   0.997  
Ramshot Wild Boar                   92.3     40.9     2.65    2527    99.7    61641   11199   1.007  
Hodgdon H4895                       93.8     38.9     2.52    2525    99.9    61641   11112   1.012  
IMR 3031                            96.9     37.6     2.44    2519   100.0    61641   10287   1.014  
Accurate 2520                       92.1     40.3     2.61    2512   100.0    61641   10567   1.025  
Accurate 4064                       99.2     40.3     2.61    2511   100.0    61641   10564   1.042  
Hodgdon VARGET                      99.8     40.1     2.60    2506    99.4    61641   10976   1.003  
Ramshot TAC                         92.1     41.2     2.67    2502    98.2    61641   11165   1.009  
Vihtavuori N530                     90.5     37.8     2.45    2501   100.0    61641   10624   1.011  
IMR 4064                           100.5     39.4     2.55    2500    99.5    61641   10796   1.008  
IMR 4007 SSC                       100.1     42.1     2.73    2497    96.1    61641   11297   1.012  
IMR 4350                           106.0     43.8     2.84    2495    95.7    59794   11388   1.014  
IMR 8208 XBR                        92.5     38.4     2.49    2495   100.0    61641   10534   1.010  
Vihtavuori N540                     96.9     40.7     2.63    2494   100.0    61641   10433   1.016  
Norma 201                           95.2     38.7     2.51    2493   100.0    61641   10624   1.024  
Norma 202                           94.6     38.6     2.50    2491   100.0    61641   10256   1.018  
Accurate 2495                       93.3     37.9     2.46    2490   100.0    61641   10120   1.049  
Ramshot X-Terminator                89.8     39.8     2.58    2483    99.6    61641   10626   1.012

The order of the powders, sorted by velocity, generally does not change. There are a few exceptions, but it can be said that generally speaking the powder that yields the highest velocity in a given barrel length will also yield the highest velocity in a shorter barrel.

There is a little difference in the completion of the burn (between the two barrel lengths), but that small amount of additional burn in the longer barrel cannot contribute to higher velocity because by the time it occurs, the volume of the gas behind the bullet in the bore is so great that the small additional percentage of the charge burning cannot contribute to the time-pressure curve sufficiently to make any real difference.

"Arguing with you always makes me thirsty."

-Augustus McRae

Re: Burn rate and barrel length [Re: Cleric] #6178072 02/10/16 10:48 PM
Joined: Mar 2012 Posts: 3,809 C Cleric OP Extreme Tracker
OP Cleric Extreme Tracker C Joined: Mar 2012 Posts: 3,809	Awesome info. Surprised 4451 is not on there Btw... Just realized I am in your sig

Re: Burn rate and barrel length [Re: Cleric] #6178123 02/10/16 11:10 PM
Joined: Nov 2007 Posts: 9,521 Wise Co. R RiverRider THF Trophy Hunter
RiverRider THF Trophy Hunter R Joined: Nov 2007 Posts: 9,521 Wise Co.	I wish it was!! The QL database for powder is not up to the latest developments. I've been waiting for LT-32 to be added for several years now. And Ramshot Wild Boar?? I don't believe I've ever heard of it...but, CRS, ya know. Yes, I thought your post in a recent thread that turned horribly ugly would make a good sig line. "Arguing with you always makes me thirsty." -Augustus McRae

Re: Burn rate and barrel length [Re: Cleric] #6178175 02/10/16 11:57 PM
Joined: Oct 2012 Posts: 29,604 Weatherford, TX S Sneaky THF Celebrity
Sneaky THF Celebrity S Joined: Oct 2012 Posts: 29,604 Weatherford, TX	I've learned quite a bit since I started paying attention to RiverRider.

Re: Burn rate and barrel length [Re: Cleric] #6178209 02/11/16 12:29 AM
Joined: Jun 2012 Posts: 1,835 DFW 5 5 Stand Dan Pro Tracker
5 Stand Dan Pro Tracker 5 Joined: Jun 2012 Posts: 1,835 DFW	Years ago, there was an article in Precision Shooting on this very topic. They took a bunch of long barrels, found the powder with the highest FPS for each tube, then started cutting the barrel shorter and re-tested. They found that with any specific barrel, the powder that worked best in a long barrel worked best as it got shorter. I found an interesting set of articles about barrel length vs. velocity that are cartridge specific.

Re: Burn rate and barrel length [Re: Cleric] #6178642 02/11/16 06:02 AM
Joined: Sep 2006 Posts: 32,494 Texas kmon11 junior
kmon11 junior Joined: Sep 2006 Posts: 32,494 Texas	RiverRider, lots of this discussion looks familiar. Chad another screen in quickloads that shows some more good information is use the Table instead of graph representation in the default lower left hand corner. Save the file and compare some. That one will show pressure, velocity and burn percentage as the bullet travels down the barrel. Peak pressure happens within the first 2 inches of bullet travel then starts dropping off. Remember by the time a bullet has traveled 2 inches it has gone from stop to being in motion and has had the rifling engraved into the bullet. With most powders the amount of powder burned is many times more in the first half of the barrel than the last half of the barrel, like RR pointed out most is burned in the first 10 inches with very little the rest of the way. for example Cartridge : .308 Win. (CIP) Bullet : .308, 168, Nosler CC HPBT J4 53164 Useable Case Capaci: 49.301 grain H2O = 3.201 cm� Cartridge O.A.L. L6: 2.800 inch = 71.12 mm Barrel Length : 22.0 inch = 558.8 mm Powder : Hodgdon VARGET Charge : 45.0 grains = 2.92 grams Estimates of the progress of combustion: NR.: x(in.) Z(%) v(fps) p(psi) t (ms) 0 0.00000 1.31 0.0 3626 0.0000 1 0.00002 1.34 0.7 3726 0.0015 2 0.00007 1.42 2.2 3927 0.0045 3 0.00019 1.47 3.3 4077 0.0084 4 0.00044 1.56 5.1 4326 0.0132 5 0.00087 1.67 7.3 4625 0.0190 6 0.00154 1.81 10.0 4998 0.0254 7 0.00255 1.97 13.3 5443 0.0326 8 0.00398 2.16 17.3 5972 0.0405 9 0.00595 2.39 21.8 6583 0.0488 10 0.00857 2.66 27.2 7299 0.0578 11 0.01197 2.97 33.5 8129 0.0671 12 0.01630 3.33 40.8 9081 0.0768 13 0.02170 3.75 49.2 10162 0.0868 14 0.02834 4.23 58.8 11388 0.0971 15 0.03641 4.78 69.8 12757 0.1075 16 0.04608 5.40 82.3 14280 0.1181 17 0.05756 6.11 96.5 15968 0.1288 18 0.07106 6.90 112.3 17809 0.1396 19 0.08681 7.78 130.1 19801 0.1504 20 0.10504 8.77 149.9 21942 0.1613 21 0.12600 9.86 171.8 24217 0.1721 22 0.14995 11.07 195.9 26607 0.1830 23 0.17716 12.39 222.3 29090 0.1938 24 0.20792 13.83 251.1 31637 0.2047 25 0.24252 15.39 282.2 34222 0.2155 26 0.28127 17.07 315.8 36804 0.2263 27 0.32448 18.87 351.7 39353 0.2371 28 0.37249 20.80 390.0 41829 0.2478 29 0.42564 22.84 430.7 44202 0.2586 30 0.48428 25.00 473.6 46432 0.2694 31 0.54879 27.27 518.6 48496 0.2803 32 0.61953 29.65 565.7 50363 0.2912 33 0.69690 32.12 614.7 52012 0.3021 34 0.78130 34.69 665.5 53428 0.3131 35 0.87314 37.34 717.9 54602 0.3241 36 0.97285 40.08 771.7 55525 0.3353 37 1.08087 42.88 826.8 56200 0.3466 38 1.11751 43.79 844.9 56365 0.3502 39 1.17739 45.19 872.5 56498 0.3560 40 1.20797 45.88 886.3 56533 0.3589 41 1.22343 46.23 893.2 56544 0.3604 42 1.23900 46.57 900.1 56549 0.3618 43 1.24291 46.66 901.8 56550 0.3622 44 1.24683 46.74 903.5 56550 0.3625 45 1.24781 46.76 904.0 56550 0.3626 46 1.24879 46.78 904.4 56550 0.3627 47 1.24977 46.81 904.8 56550 0.3628 48 1.37922 49.50 960.1 56401 0.3744 49 1.51675 52.13 1015.3 55976 0.3860 50 1.66313 54.69 1070.5 55305 0.3977 51 1.81920 57.18 1125.7 54416 0.4095 52 1.98587 59.60 1181.0 53333 0.4216 53 2.16415 61.94 1236.2 52080 0.4339 54 2.35516 64.22 1291.4 50680 0.4464 55 2.56014 66.43 1346.7 49153 0.4594 56 2.78046 68.56 1401.9 47519 0.4728 57 3.01765 70.63 1457.1 45797 0.4866 58 3.27344 72.63 1512.3 44002 0.5009 59 3.54975 74.55 1567.6 42151 0.5159 60 3.84875 76.41 1622.8 40259 0.5315 61 4.17288 78.19 1678.0 38339 0.5479 62 4.52491 79.91 1733.3 36403 0.5651 63 4.90797 81.55 1788.5 34464 0.5832 64 5.32564 83.13 1843.7 32532 0.6024 65 5.78198 84.63 1898.9 30616 0.6227 66 6.28166 86.07 1954.2 28726 0.6443 67 6.83003 87.43 2009.4 26870 0.6674 68 7.43328 88.72 2064.6 25053 0.6920 69 8.09854 89.95 2119.8 23284 0.7185 70 8.83411 91.10 2175.1 21568 0.7471 71 9.64965 92.18 2230.3 19909 0.7779 72 10.55649 93.19 2285.5 18313 0.8114 73 11.56793 94.14 2340.8 16781 0.8478 74 12.69972 95.01 2396.0 15318 0.8877 75 13.97053 95.81 2451.2 13926 0.9314 76 15.40266 96.54 2506.4 12607 0.9795 77 17.02286 97.20 2561.7 11361 1.0328 78 18.86346 97.80 2616.9 10190 1.0920 79 19.87836 98.06 2644.5 9632 1.1242 80 20.14286 98.13 2651.4 9496 1.1325 81 20.27679 98.16 2654.9 9428 1.1367 82 20.34418 98.18 2656.6 9394 1.1388 83 20.36108 98.18 2657.0 9386 1.1394 84 20.36953 98.18 2657.2 9382 1.1396 85 20.37376 98.18 2657.3 9380 1.1398 86 20.37481 98.18 2657.4 9379 1.1398 87 20.37534 98.18 2657.4 9379 1.1398 88 20.37561 98.18 2657.4 9379 1.1398 Muzzle To see an example of powders burning more efficiently under pressure, look how slow a charge of powder for a load burns when just poured into an iron skillet and not contained by anything, even fast handgun or shotshell powder will burn very slowly and produce a lot of smoke for a "smokeless" powder. Last edited by kmon1; 02/11/16 06:16 AM. lf the saying "Liar, Liar your pants on fire" were true Mainstream news might be fun to watch

Re: Burn rate and barrel length [Re: Sneaky] #6178643 02/11/16 06:05 AM
Joined: Sep 2006 Posts: 32,494 Texas kmon11 junior
kmon11 junior Joined: Sep 2006 Posts: 32,494 Texas	Originally Posted By: Sneaky I've learned quite a bit since I started paying attention to RiverRider. Good man to pay attention to lf the saying "Liar, Liar your pants on fire" were true Mainstream news might be fun to watch

Re: Burn rate and barrel length [Re: kmon11] #6178777 02/11/16 01:51 PM
Joined: Dec 2008 Posts: 41,171 Wolfe City, TX J.G. THF Celebrity
J.G. THF Celebrity Joined: Dec 2008 Posts: 41,171 Wolfe City, TX	Originally Posted By: kmon1 Originally Posted By: Sneaky I've learned quite a bit since I started paying attention to RiverRider. Good man to pay attention to ^^Both of these guys are.^^ Great thread. 800 Yard Steel Range Precision Rifle Instruction Memberships and Classes Available

Re: Burn rate and barrel length [Re: Cleric] #6179014 02/11/16 04:32 PM
Joined: Mar 2012 Posts: 3,809 C Cleric OP Extreme Tracker
OP Cleric Extreme Tracker C Joined: Mar 2012 Posts: 3,809	So in conclusion my hypothesis was way wrong. I thought the quicker burn time would work comparatively better than slower burn powders. But if I can get a 162 grain bullet 2500+ it should carry 1000 ft lbs out to 400+

Re: Burn rate and barrel length [Re: Cleric] #6179023 02/11/16 04:39 PM
Joined: Nov 2007 Posts: 9,521 Wise Co. R RiverRider THF Trophy Hunter
RiverRider THF Trophy Hunter R Joined: Nov 2007 Posts: 9,521 Wise Co.	Cleric, naturally you'll be most interested in accuracy but not totally ignoring velocity. I would suggest that you might consider muzzle blast too. The slower burning powders get you higher muzzle pressures and corresponding noise. Some have suggested that higher pressure at the muzzle when the bullet exits might contribute to a bit of upset to the bullet, I guess you'd call it yaw. I have no idea just how true and / or significant it might be. "Arguing with you always makes me thirsty." -Augustus McRae

Re: Burn rate and barrel length [Re: Cleric] #6179028 02/11/16 04:41 PM
Joined: Dec 2008 Posts: 41,171 Wolfe City, TX J.G. THF Celebrity
J.G. THF Celebrity Joined: Dec 2008 Posts: 41,171 Wolfe City, TX	Originally Posted By: Cleric So for a 7mm-08 with an 18in barrel what type of powder speed am I looking for? Ideally I could use something in the 162 grain area My 7mm-08 is a 20" barrel, plus 10" suppressor. 162 gr A-Max H-Varget 39.9 gr 2635 fps MV 800 Yard Steel Range Precision Rifle Instruction Memberships and Classes Available

Re: Burn rate and barrel length [Re: RiverRider] #6179064 02/11/16 05:05 PM
Joined: Mar 2012 Posts: 3,809 C Cleric OP Extreme Tracker
OP Cleric Extreme Tracker C Joined: Mar 2012 Posts: 3,809	Originally Posted By: RiverRider Cleric, naturally you'll be most interested in accuracy but not totally ignoring velocity. I would suggest that you might consider muzzle blast too. The slower burning powders get you higher muzzle pressures and corresponding noise. Some have suggested that higher pressure at the muzzle when the bullet exits might contribute to a bit of upset to the bullet, I guess you'd call it yaw. I have no idea just how true and / or significant it might be. Who needs accuracy when you have power??

Re: Burn rate and barrel length [Re: Cleric] #6182783 02/14/16 02:28 PM
Joined: Mar 2012 Posts: 3,809 C Cleric OP Extreme Tracker
OP Cleric Extreme Tracker C Joined: Mar 2012 Posts: 3,809	Has anyone experimented With the 195 in 7mm-08? From the numbers I ran even with the reduced velocity it has for more power than the 162 class bullets.

Re: Burn rate and barrel length [Re: Cleric] #6182815 02/14/16 02:58 PM
Joined: Dec 2008 Posts: 41,171 Wolfe City, TX J.G. THF Celebrity
J.G. THF Celebrity Joined: Dec 2008 Posts: 41,171 Wolfe City, TX	I expect it to be like a 208 gr. in a .308 Win. It'll run extremely slow and not be very good for distance. The bullet is also very long, to get it to mag length you're gonna have a ton of bullet in the case. You'll need a 1:8" twist to stabilize it. My 1:8.5 twist 7 Rem Mag stabilized the 195, but it has a whole lot more powder behind it than the 7-08. Even then it made 2850 fps, which is not enough velocity to out perform the 180 gr @ 3030 fps MV out of the same rifle. 168 gr is the heaviest/ longest bullet I would run in a 7-08, no matter barrel length. There comes a point of diminishing returns, when you gain BC and weight, but can't push it fast enough to take advantage of that BC and weight. Just my opinion. 800 Yard Steel Range Precision Rifle Instruction Memberships and Classes Available

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