25 Creedmoor / 135 Berger Lot to Lot Consistency

[Porthunter]

I went to the range with a new lot of Berger 135s yesterday loaded exactly to what my previous load was. Previous load averaged 10 shot groups at .20-.22 MR and .7-.8 MOA

Yesterday, a 5 shot group produced a result of .38MR and .85 MOA.

I decided to measure the loaded projectiles and with this new lot, 2.155CBTO gives me a jump of 65 thou where my previous load it was a jump of 45 thou. Seems like quite substantial difference.

For context, I measured throat erosion 100rds ago when the rifle had approx. 350 rds through it and the throat had only eroded about 6 thou through that.

The changes that I made to system outside of lot change were;

- AMP Annealed but brass was sized in bushing die with same mandrel ran through
- Primer pockets were slightly reamed with Lyman reamer hand took
- Scope swap from NX8 2.5-20 MOAR to NX8 4-32 MILXT

Has anyone experienced substantial changes with Berger’s lot to lot?

I will be loaded these new ones at 45 thou jump again and trying that as well for 10 shots.

 

[KY_coop]

How many rounds have you shot since you last measured? Your group sizes seem close enough to be considered normal IMO. if you have a lot of rounds down it since you last measured it could be the lands getting burnt out. .020" ish.
Im no genius at this stuff though, seems like its still shooting pretty well to me

 

[huntnful]

If you annealed, and then used the same bushing and mandrel as before, you greatly lowered your neck tension than the previous rounds you didn’t anneal.

Also, if you have a single bullet from the previous lot, just measure each bullet individually for comparison. I’m hesitant to believe the O-give is off .025 between lots of Berger’s. But I’ve seen as much as .040 difference between lots of ELDM’s. So it’s possible.

 

[Porthunter]

If you annealed, and then used the same bushing and mandrel as before, you greatly lowered your neck tension than the previous rounds you didn’t anneal.

Also, if you have a single bullet from the previous lot, just measure each bullet individually for comparison. I’m hesitant to believe the O-give is off .025 between lots of Berger’s. But I’ve seen as much as .040 difference between lots of ELDM’s. So it’s possible.

Confirmed that the ogive was off about 19 thou. I have another lot that is off by 11 thou on the shelf too. I went and adjuster for the jump difference aswell as cleaned my muzzle brake and a quick couple patches down the barrel and this was the result. Bottom two were the first two after cleaning than 8 stacked in.

 

[Firestone]

Yeah there was one lot of 135s that were released not to long ago that were "bad". Might be the lot you got. Email berger and if it is the bad lot # they will replace them for you.

 

[Porthunter]

Yeah there was one lot of 135s that were released not to long ago that were "bad". Might be the lot you got. Email berger and if it is the bad lot # they will replace them for you.

Good to know. I’ll flip them an email now.

 

[sierracharlie338]

If you get a lot number please share but the two or three lots I have been through so far have shown no issues.

 

[huntnful]

Confirmed that the ogive was off about 19 thou. I have another lot that is off by 11 thou on the shelf too. I went and adjuster for the jump difference aswell as cleaned my muzzle brake and a quick couple patches down the barrel and this was the result. Bottom two were the first two after cleaning than 8 stacked in.

Good to know! Thank you for the update