Main Menu
Advertisement
Affiliates
Advertisement
Newest Members
AA0605, HookEm01, Gambler 25-06, JWRivette, Adchunts
60416 Registered Users
Top Posters
dogcatcher 77349
stxranchman 52092
RWH24 44568
rifleman 43781
BOBO the Clown 41084
BMD 40539
Big Orn 37484
txshntr 33682
bill oxner 32601
sig226fan (Rguns.com) 30565
facebook
Forum Stats
60416 Members
45 Forums
475645 Topics
6239630 Posts

Max Online: 16728 @ 03/25/12 08:51 AM
Topic Options
#6480865 - 10/04/16 04:51 PM Pressure & velocity
jlsbassman Online   content


Registered: 06/18/09
Posts: 344
Loc: Royse City
If velocity is an indicator of high pressure, how do you know at what velocity your running to much pressure?

Top
#6480914 - 10/04/16 05:15 PM Re: Pressure & velocity [Re: jlsbassman]
RiverRider Online   content
THF Trophy Hunter

Registered: 11/11/07
Posts: 6203
Loc: Wise Co.
One way is to compare your velocity to what's shown in a reloading table using the same bullet and powder, but sometimes that isn't very reliable because load data can be based on results using special pressure barrels. It's bad enough that there can be wide disparities between similar, everyday rifles.

Another way is to use a good internal ballistics program like QuickLOAD. Even then, you have to take variables into account and you may still be off in the weeds a little.

There are cases when it's pretty easy, though. If you know that a top .243 load using H4831 will get you 3000 fps with your favorite 100-grain bullet, and you happen to be playing with Varget one day for a change, a velocity of 3050 fps should be a great big red flag. Make sense?
_________________________


Originally Posted By: Cleric
God I am hating caliber threads more and more

Top
#6481798 - 10/05/16 09:48 AM Re: Pressure & velocity [Re: jlsbassman]
Jgraider Online   content
Bird Dog

Registered: 06/13/15
Posts: 263
Loc: West Texas
+1 to what RiverRider said.

I take a cross section of about 5 different sources when looking for starting and max loads, and work up accordingly, which is why a chrono is mandatory IMO. For instance, I have a McWhorter 7-08 that likes 140 Accubonds. When I reach 2800 fps I start proceeding with caution, and even though I theoretically could get to 2900' lets say, I'd have to assume pressure would be an issue. There is no way to know exactly what pressures you're running without the proper equipment.

Top
#6481822 - 10/05/16 10:05 AM Re: Pressure & velocity [Re: jlsbassman]
redchevy Offline
THF Celebrity

Registered: 10/25/04
Posts: 23348
Loc: Texas
Kinda tuff to say. I don't think published load data MAX load really equals MAX pressure, I'm sure there is a little wiggle room built in.

I typically don't push the max load area too much, if I can get an accurate load at a lower node I accept burning less powder and longer case/barrel life and a smidge less report and recoil and go on about life. I hear people talking about loading over book max all the time and see people talk about getting 3150 fps out of a 243 100 grain often, which from what I have read is well over published maxes. I loaded groups of 4 in .3 grain increments to .2 grain over max this weekend in my 243 and my highest charge had no observed differences in case/primer/bolt lift than the lower charges except it hit a little higher on the paper at 200 yards. Any one have an idea of how much wiggle room they leave you past book max loads? I know it probably varies from rifle to rifle etc. I guess I shoot in the dark, I haven't added a chrono to my loading equipment yet, but plan to some day.
_________________________
It's hell eatin em live

Top
#6482104 - 10/05/16 12:36 PM Re: Pressure & velocity [Re: jlsbassman]
bo323 Offline
Tracker

Registered: 09/24/11
Posts: 706
Loc: Snyder, tx
They don't always leave wiggle room. My 257 wby max was 73 gr. That was the published max. I changed brass at 71 grains I blew a primer. New max is 70. Start low and work up always. I went from wby brass to hornady.

Top
#6482298 - 10/05/16 02:16 PM Re: Pressure & velocity [Re: jlsbassman]
RiverRider Online   content
THF Trophy Hunter

Registered: 11/11/07
Posts: 6203
Loc: Wise Co.
Had similar goings on with a .243 a few years back.
_________________________


Originally Posted By: Cleric
God I am hating caliber threads more and more

Top
#6482673 - 10/05/16 06:27 PM Re: Pressure & velocity [Re: RiverRider]
OkieDokie Online   happy
Tracker

Registered: 01/28/08
Posts: 733
Loc: southern OK
Originally Posted By: RiverRider
Had similar goings on with a .243 a few years back.

I had the same thing on my 243 had a sticky bolt way before max load was reached.
_________________________
Maybe Today.
raptureready.com

Top
#6484722 - 10/06/16 11:33 PM Re: Pressure & velocity [Re: jlsbassman]
jlsbassman Online   content


Registered: 06/18/09
Posts: 344
Loc: Royse City
What do you all think the max velocity I should be able get from a 243win with 105gr amax using H4350, hybrid 100v and h1000. 26 inch barrel.

Top
#6485364 - 10/07/16 12:44 PM Re: Pressure & velocity [Re: jlsbassman]
Burton Ranch Offline
Light Foot

Registered: 05/21/12
Posts: 37
I know this does not address your question specifically, but I am loading 42.8 grns of H4831sc with a WLR primer and a 105 Berg Vld. This load avg around 2900 fps. This is out of an RPR. Hope this might help in some way.

Top
#6485405 - 10/07/16 01:35 PM Re: Pressure & velocity [Re: jlsbassman]
jlsbassman Online   content


Registered: 06/18/09
Posts: 344
Loc: Royse City
Burton Ranch, where you seeing any pressure signs with the load? I have been using 105 amax, running a load of 41.8gr of hybrid 100v and was getting 3120fps out of it with no pressure signs at all. I ran some loads Saturday with Berger 105 hybrid match from 39gr to 42gr and had zero sign of pressure. That's why I have been concerned about the velocity as everyone talks about the speed as one of the signs of high pressure.

Top
#6485531 - 10/07/16 03:11 PM Re: Pressure & velocity [Re: jlsbassman]
Burton Ranch Offline
Light Foot

Registered: 05/21/12
Posts: 37
No sir, I have not seen any pressure signs. I am on my 4th reload with the same brass and still shoots great groups. In regards to your question regarding the correlation between velocity and pressure, I posted a similar question. I believe the consensus was that the only way to truly determine pressure in your rifle is the combination of specialized equipment and software. Simply plugging the numbers in would only give you an estimate and might not even be close. I inquired due to the fact I had a load for 6.5 cm that was getting way over max with no signs of pressure issues. I was trying calculate pressure based on the load and velocity. I am just getting started reloading but have found that much like life, the more I learn I realize how little I know.

Top



© 2004-2016 OUTDOOR SITES NETWORK all rights reserved USA and Worldwide