Main Menu
Advertisement
Affiliates
Advertisement
Newest Members
JLadner, bubbleheadhunter775, Casper, Grandpa Jay, B bar W
60403 Registered Users
Top Posters
dogcatcher 77304
stxranchman 52092
RWH24 44568
rifleman 43776
BOBO the Clown 41081
BMD 40539
Big Orn 37484
txshntr 33682
bill oxner 32555
sig226fan (Rguns.com) 30552
facebook
Forum Stats
60403 Members
45 Forums
475474 Topics
6237513 Posts

Max Online: 16728 @ 03/25/12 08:51 AM
Page 1 of 2 1 2 >
Topic Options
#5406177 - 11/07/14 10:04 PM Mauser Miss-Behav'n
StraitShot Offline
Bird Dog

Registered: 09/12/10
Posts: 327
Loc: Republic of Texas
Question:

1)First shot is always high, second shot low, grouping gone. What would cause this ?
2)Bullets striking high at 200yrds like they did at 100yrds, no scope adjustment. How is that possible ?

Components and Pics below.... Thoughts or suggestions appreciated....


Components:
Shilen Barrel – 24”, 1:9
Caliber: 7x57
Bullet: 139gr SST
Powder: H4350 at 40gr @ 2200fps
Case: Norma

Went to the range today to do some work with the 7mm Mauser. I had previously sighted her in at 200yrds but had to do a little bench work so went back to the 100yrd and rechecked. Got a reasonable group of about ¾ inch and around 3 inches high – what I would have expected. Using a light load of powder just to get the initial work done. Barrel was fouled appropriately, no cleaning between groups.

Target 1
http://i1311.photobucket.com/albums/s670/shutter83dog/100yrdSightIn11072014_zpsd2823053.jpg

Having verified I was on paper I went back to the 200yrd and took some target practice, getting ready to test some rounds for bullet seating depth. I noticed some odd behavior. 1) The first shot was always high, the second one low and the others in between. Gone was the nice group at 100yrds. The other item… 2) I expected the bullets to strike the middle of the target (not at the top like on the 100ydr target)….. as you can see they are strung pretty high and I did not make any scope adjustment.

5 rounds with bullet seated on the lands 3.75 inch group at 200yrds
http://i1311.photobucket.com/albums/s670/shutter83dog/200yrds-TouchingLands11072014_zps280899a4.jpg

5 rounds with bullets seated .001 off the lands 2.63 inch group at 200yrds
http://i1311.photobucket.com/albums/s670/shutter83dog/200yrds-001OffLands11072014_zpsdf7c17a0.jpg

5 rounds with bullets seated .002 off the lands 1.79 inch group at 200yrds (Best)
http://i1311.photobucket.com/albums/s670/shutter83dog/200yrds-002OffLands11072014_zps57caf8b3.jpg

5 rounds with bullets seated .003 off the lands 4.15 inch group at 200yrds
http://i1311.photobucket.com/albums/s670/shutter83dog/200yrds-003OffLands11072014_zps32e5a1cf.jpg

Top
#5406194 - 11/07/14 10:19 PM Re: Mauser Miss-Behav'n [Re: StraitShot]
Geezer Ranger Online   happy
Pro Tracker

Registered: 05/06/13
Posts: 1597
Loc: Ft Worth, Texas
I suspect the key is the "light load" you mention. All of your targets are showing vertical stringing. I would guess you are NOT moving the bullet fast enough to stabilize at longer ranges. I think you will need to get it up to 2500 to 2600 fps to stabilize it at 200 yards.
_________________________
texas I am allergic to stupidity. You can't fix Stupid, but you can occasionally head it off before it hurts something.

Top
#5406266 - 11/07/14 11:50 PM Re: Mauser Miss-Behav'n [Re: StraitShot]
RiverRider Online   content
THF Trophy Hunter

Registered: 11/11/07
Posts: 6194
Loc: Wise Co.
Doesn't look anyhting like a stability issue to me.

Light loads of slower burning powders don't ignite and burn with the consistency they will at higher pressures. Smokeless powders are progressive burning and that means the higher the pressure, the faster they burn and the faster they burn, the higher the pressure (and it's easy to see why it can get out of hand with an overcharge). But the bottom line is that a powder that is meant to operate at 50,000 psi isn't going to work consistently if the peak pressure is 20,000 psi. Not saying that's your pressure, just using dramatic extremes to make the point.
_________________________


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

Top
#5406270 - 11/07/14 11:59 PM Re: Mauser Miss-Behav'n [Re: StraitShot]
RiverRider Online   content
THF Trophy Hunter

Registered: 11/11/07
Posts: 6194
Loc: Wise Co.
I'll go ahead and throw this out there..against my better judgement and I hope I'm not sorry.

There are nodes of accuracy at different ranges. What works well at 100 yards may not work so well at 200 or 300 yards. The benchresters, or at least some of them, have figured this out.
_________________________


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

Top
#5406273 - 11/08/14 12:04 AM Re: Mauser Miss-Behav'n [Re: StraitShot]
RiverRider Online   content
THF Trophy Hunter

Registered: 11/11/07
Posts: 6194
Loc: Wise Co.
...and about POI being high at 200 like it is at 100, you need to just take a look at some trajectory charts. Take into account the height of your scope over the bore and think about it after you've looked at the charts.
_________________________


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

Top
#5406684 - 11/08/14 09:50 AM Re: Mauser Miss-Behav'n [Re: StraitShot]
syncerus Online   content
Pro Tracker

Registered: 12/01/08
Posts: 1989
Loc: Dallas, TX
It looks like a scope parallax problem to me.
_________________________
NRA Endowment & DSC Lifer

Top
#5406724 - 11/08/14 10:10 AM Re: Mauser Miss-Behav'n [Re: StraitShot]
kmon1 Online   content
junior

Registered: 09/27/06
Posts: 20282
Loc: Texas
I think RR and Geez are right about the powder choice for a reduced load. H4350 is slow burning and not the best choice for a reduced load, I would expect high extreme spread with it and that lite a powder charge. Might try H4895 or A5744 for that application. Both are faster burning and easy to ignite powders that lend themselves well for reduced loads.

Is the 2200fps measured or expected from some printed source. If measured what it the extreme spread? I would guess probably high and the further out the more dramatic the vertical stringing will be due to the high and low velocities.

Of course I could be wrong but if looking for a reduced load I look to the 2 powders above for good results.
_________________________
Guidelines / Rules of Conduct
http://www.texashuntingforum.com/rules.htm

RULES for using the TRADING POST
http://www.texashuntingforum.com/forum/u..._PO#Post1959111

Top
#5406760 - 11/08/14 10:37 AM Re: Mauser Miss-Behav'n [Re: syncerus]
StraitShot Offline
Bird Dog

Registered: 09/12/10
Posts: 327
Loc: Republic of Texas
Originally Posted By: syncerus
It looks like a scope parallax problem to me.


Explain please ? I have a Leupold with adjustable objective (in this case set to 200yrds). And the bench work I mentioned above was an adjustment.

I am considering what RiverRider and Kmon1 are pointing out. When I am doing load workup, I always start low and work up but I've never seen a spread as bad as that before. My "go to" loads always end up at the higher end of the powder charge chart as a result of the testing though. Maybe I am wrong on this but the bullet seating that was .002 off the lands "seemed" to be the best - maybe this was because the pressure (not being on the lands) was in a relative sense more stable ? In any case the 40grs of H4350 is just my starting point. I don't expect I will stay there....

Kmon1 - the 2200fps is from the Hornady manual - not measured on the rifle. So, should I use the adjusted seating depth and continue up the charge weight scale ?

Top
#5406782 - 11/08/14 10:54 AM Re: Mauser Miss-Behav'n [Re: StraitShot]
kmon1 Online   content
junior

Registered: 09/27/06
Posts: 20282
Loc: Texas
I usually work up in powder charge then play with seating depth once an accuracy node is found.

I think I would keep the best seating depth found so far and workup on the powder charge.
_________________________
Guidelines / Rules of Conduct
http://www.texashuntingforum.com/rules.htm

RULES for using the TRADING POST
http://www.texashuntingforum.com/forum/u..._PO#Post1959111

Top
#5406797 - 11/08/14 11:09 AM Re: Mauser Miss-Behav'n [Re: StraitShot]
kmon1 Online   content
junior

Registered: 09/27/06
Posts: 20282
Loc: Texas
Hodgdon lists a starting charge of 43gr for a 139gr bullet and my guess is with that powder you will see accuracy/consistency improving as the powder charge is increased.
_________________________
Guidelines / Rules of Conduct
http://www.texashuntingforum.com/rules.htm

RULES for using the TRADING POST
http://www.texashuntingforum.com/forum/u..._PO#Post1959111

Top
#5406820 - 11/08/14 11:25 AM Re: Mauser Miss-Behav'n [Re: kmon1]
StraitShot Offline
Bird Dog

Registered: 09/12/10
Posts: 327
Loc: Republic of Texas
Originally Posted By: kmon1
Hodgdon lists a starting charge of 43gr for a 139gr bullet and my guess is with that powder you will see accuracy/consistency improving as the powder charge is increased.


hammer And this is why we should always check alternative data sources.... I am such a goof and I now have a ready source of fouling rounds... bang on the bright side, it also shows why checking loads at longer distances is meaningful. I like to shoot at 200yrds but had I stopped at 100yrds I likely would not have seen this.....

Thank you... up

Top
#5406987 - 11/08/14 01:52 PM Re: Mauser Miss-Behav'n [Re: StraitShot]
syncerus Online   content
Pro Tracker

Registered: 12/01/08
Posts: 1989
Loc: Dallas, TX
As I look at your targets, the most obvious difference between your 100 and 200 yard targets is vertical stringing. Vertical stringing is usually caused by inconsistent rifle bedding and barrel heating, but you had no such problem at 100 yards, so I would tend to eliminate that as the primary factor. 2200 fps is fairly low velocity, so I would expect to see more significant lateral variation due to wind than I would with a higher velocity round. I don't know what the conditions were like when you were shooting, so I can't make a definite observation on that factor. Another common cause of large variation in groups between 100 and 200 yards is thick cross hairs which can lead to an inconsistent sight picture. Again, I don't know anything about your scope, so I can't comment. Finally, the large variation in the vertical stringing, once we eliminate barrel heating, really looks like an inconsistent sight picture / cheek weld or incorrect scope parallax. Since you've got a nice group at 100, I would tend to eliminate the cheek weld as a factor and focus on either an inconsistent sight picture or parallax.

I don't think the problem is the rifle or the load. You might try changing targets to achieve a better sight picture with your existing scope, changing scopes as a test, or adjusting the parallax on your scope to give yourself the very clearest sight picture rather than simply setting it to 200 yards.
_________________________
NRA Endowment & DSC Lifer

Top
#5407014 - 11/08/14 02:16 PM Re: Mauser Miss-Behav'n [Re: syncerus]
StraitShot Offline
Bird Dog

Registered: 09/12/10
Posts: 327
Loc: Republic of Texas
Thank you for your points....

The scope is a Leupold VX-III 4.5-14X40mm with fine duplex. The objective is adjustable as well. I have noticed in this scope more than the others I have (which are duplex) that this one seems to be a bit finicky on the parallax - one of the reasons she was back on the bench. However, the site picture is very good. I can see the fine lines on the target at 200yrds so a 1 inch circle is no issue.

The wind was from my back to the target and although breezy - not your typical Texas wind - kinda mild. And I had the same thoughts about the bedding and barrel touching when heated. Checked at the range and it was fine. I did extensive work on the stock and feel comfortable with it.

I think that for now, I am going to restart my load testing at 43grs of H4350 and continue to see if I can work the parallax. It is annoying and slows me down a bit... up

Top
#5408071 - 11/09/14 07:26 AM Re: Mauser Miss-Behav'n [Re: StraitShot]
Rocklock Offline
Bird Dog

Registered: 08/09/10
Posts: 395
Loc: Cedar Valley, Travis Co., TX
Old saying about grouping: Up and down increase the charge, Left and right reduce the charge.
_________________________
The answer is FLINTLOCK! Now, what was the question?

Support the Texas Youth Hunting Program
http://texasyouthhunting.com/

Top
#5408640 - 11/09/14 01:48 PM Re: Mauser Miss-Behav'n [Re: RiverRider]
Geezer Ranger Online   happy
Pro Tracker

Registered: 05/06/13
Posts: 1597
Loc: Ft Worth, Texas
Originally Posted By: RiverRider
Doesn't look anyhting like a stability issue to me.

Light loads of slower burning powders don't ignite and burn with the consistency they will at higher pressures. Smokeless powders are progressive burning and that means the higher the pressure, the faster they burn and the faster they burn, the higher the pressure (and it's easy to see why it can get out of hand with an overcharge). But the bottom line is that a powder that is meant to operate at 50,000 psi isn't going to work consistently if the peak pressure is 20,000 psi. Not saying that's your pressure, just using dramatic extremes to make the point.
_________________________
texas I am allergic to stupidity. You can't fix Stupid, but you can occasionally head it off before it hurts something.

Top
Page 1 of 2 1 2 >



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