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Help with troubleshooting

Chiquita

Chiquita

Proud Armenian
Gold $$ Contributor
I have good reloading equipment, good tools and as far as I can tell, good reloading practice. My .308 Lapua brass fired 12 times, for some reason I can not get consistent velocities out of it. I have tried Varget, IMR4064, 175 SMK, 168 Hornady and 168 SMK with Federal 210.
The grouping is within 5/8" at 100 yards. I am happy there. The velocities may jump 40 to 50 FPS on the ES. And as far as I can remember this case has been doing this. On the other hand Starline I can get same grouping and 6-9 SD and less than 20 extreme.

At this point I don't think it is my reloading equipment or technique. Can any of the following cause a spike or low velocity
bolt, firing pin, firing pin spring.

I carbon clean after every range session and throughly clean after 200 to 300 rounds.

Is it possible that the Lapua brass just doesn't work in my rifle?? If yes, please explain why and how?

Any pointers is appreciated.
 
Lots of open ended questions here.

When I think about 12x firing, I would consider: annealing and the consistency and frequency of that process, measuring brass neck thickness changes, prepping same load with newer Lapua brass to compare.

Bigger picture, ignition is a big deal: have I changed the firing pin spring lately, is my firing pin bent, do I see drag marks on the firing pin?
 
When it comes to maintaining low ES/SD, everything can matter. It doesn't always have to, but it can. That list may include (in no particular order):

1) sorting brass from a single Lot# by weight/volume
2) testing different primers with a given powder/bullet/brass combination
3) precise powder measurement/delivery
4) use of an optimum powder for a given application (i.e. bullet weight barrel length, case volume, etc.)
5) annealing after every firing
6) proper trim/chamfer
7) properly uniformed primer pockets
8) properly uniformed flash holes
9) proper firing pin protrusion
10) sufficient firing pin spring energy
11) optimized neck tension/interference fit
12) consistent neck tension/interference fit
13) consistent bullet diameter

The bad news is that there are likely a bunch of other factors that could be added to this list. The good news is you've already obtained reasonable ES/SD values using Starline brass, thereby suggesting your brass preparation process is working. Further, it suggests something is different about the Lapua brass (or the preparation it is receiving) such that it is not responding to your process as well the Starline brass. I have had brass preps that I did pretty much everything to that I know how to do and still could not obtain acceptable ES/SD values. That doesn't necessarily mean that it couldn't have been made to provide acceptable velocity numbers, only that what I did to it wasn't sufficient. The real question one must answer is how much time and effort they're willing to put into chasing better velocity numbers, especially in your case when have a different brand of brass that appears to be working acceptably. In a discipline such as F-Class for example, maintaining acceptable ES/SD is pretty important. Even so, most F-Class shooters have their limits as to how long/far they are willing to chase something down the rabbit hole.
 
Run a few of those Lapua cases past a chronograph, mark those displaying odd feet per second variations for examination and comparison to those cases within our margin, weigh and volume, primer pockets etc. it’s quite easy and quite effective.
 

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762plinker said:
what rifle, what loads/velocities
what does it do at 600 /800 yards ??
neck turned ? annealed ??
Click to expand...
It is HOWA 1500 .308
I have not done paper targets at 6-8 hundred.
Necks not turned but it is annealed every time with AMP.
 
David Christian said:
Lots of open ended questions here.

When I think about 12x firing, I would consider: annealing and the consistency and frequency of that process, measuring brass neck thickness changes, prepping same load with newer Lapua brass to compare.

Bigger picture, ignition is a big deal: have I changed the firing pin spring lately, is my firing pin bent, do I see drag marks on the firing pin?
Click to expand...
The firing pin is not bent, the spring seems to be OK. I don't see any marks on the FP.
 
SPJ said:
Run a few of those Lapua cases past a chronograph, mark those displaying odd feet per second variations for examination and comparison to those cases within our margin, weigh and volume, primer pockets etc. it’s quite easy and quite effective.
And check this out.. even if just leave those cases in the box and don’t load them again I’ve cut my ES in half.
Click to expand...
I have done this in the past, and marked the cases with the higher velocities. so, when I test them next time the cases that had high velocities are not high anymore. I did do this several times and the results were not consistent. Basically, I can't say these 15 cases always have high/low or erratic velocities.
 
Ned Ludd said:
When it comes to maintaining low ES/SD, everything can matter. It doesn't always have to, but it can. That list may include (in no particular order):

1) sorting brass from a single Lot# by weight/volume. I have done sorting in the past with this lot of brass, but gave up on sorting because on next range day the sorted cases did not have consistent velocities similar to last time. I don't know how to do volume testing.
2) testing different primers with a given powder/bullet/brass combination. I am working on this.
3) precise powder measurement/delivery. Used V3, V4 and Super Trickler. So the powder measurement is good.
4) use of an optimum powder for a given application (i.e. bullet weight barrel length, case volume, etc.). I tried IMR 4064 with SMK 175 and now I am testing Varget with Hornady 168 and SMK 168.
5) annealing after every firing. Yes I do
6) proper trim/chamfer. I don't trim to same height every time. But I know the within the chamber max measurement. Will the case height creat erratic velocities?
7) properly uniformed primer pockets. Every time with Hornady uniformer and now with 21st century uniformer. Both are adjustable,
8) properly uniformed flash holes. Did this once. I don't think I need to do again. Do I?
9) proper firing pin protrusion. I don't know how to check or test this.
11) optimized neck tension/interference fit I don't know how to test this. I use LEE collet die on teh neck FYI.
Click to expand...
Ned Ludd said:
10) sufficient firing pin spring energy. I don't know how to test this.
12) consistent neck tension/interference fit I don't know how to test this.
13) consistent bullet diameter. I guess I can sort bullets.

The bad news is that there are likely a bunch of other factors that could be added to this list. The good news is you've already obtained reasonable ES/SD values using Starline brass, thereby suggesting your brass preparation process is working. Further, it suggests something is different about the Lapua brass (or the preparation it is receiving) such that it is not responding to your process as well the Starline brass. I have had brass preps that I did pretty much everything to that I know how to do and still could not obtain acceptable ES/SD values. That doesn't necessarily mean that it couldn't have been made to provide acceptable velocity numbers, only that what I did to it wasn't sufficient. The real question one must answer is how much time and effort they're willing to put into chasing better velocity numbers, especially in your case when have a different brand of brass that appears to be working acceptably. In a discipline such as F-Class for example, maintaining acceptable ES/SD is pretty important. Even so, most F-Class shooters have their limits as to how long/far they are willing to chase something down the rabbit hole.
Click to expand...

I may just come to agreement that this Lapua batch or Lapua in general doesn't work with my rifle.

Thanks for the detailed writeup.
 
Isn't the starline thicker/heavier than lapua? If so, you should work up loads for each, respectively. How about neck to chamber clearance? Do the loaded rounds measure the same, particulary with a collet die? If one is too tight, that could explain it all but at the least, they should be the same od of the loaded round, or very close. I don't think it's ignition, if it the problem is only with Lapua...with the caveat that primer pocket depth should be the same as well as primer seating depth. Lapua brass is generally excellent so I would look other places first.
 
Are you certain your chronograph is working correctly? You might want to borrow one to compare. Just a thought. You marked the cases and there is no consistency.
Chiquita said:
I have done this in the past, and marked the cases with the higher velocities. so, when I test them next time the cases that had high velocities are not high anymore. I did do this several times and the results were not consistent. Basically, I can't say these 15 cases always have high/low or erratic velocities.
Click to expand...
 
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