Range Report Ammo speeding up

[Zack_va248]

Factory 140g eldm sped up today. Trued my dope after rezeroing a new lot of ammo and it was 300-1.0, 400-1.9, 500-2.8, 600-3.3, and 700-4.3. Based on 4dof the velocity sped up from 2715 FPS previous lot to 2835 or so. Anyone else seen this big a jump lot to lot? I typically see a tenth here or there lot to lot in dope variation but at 600 I was a full half mil high using my previous dope of 3.8. I also can’t get 4dof to line up at every yard line. It lines up at every yard line except 400 and 500. Those two remained the same as my previous slower lot at two tenths above what 4dof calls for with the higher velocity . Normal? Anyone else seen this? I’ll post the lot number later to see if anyone else noticed the variation.

 

[Steel head]

7115 FPS?


Ammo speed variations between lots totally happens
Without a true chrony speed it could be a few things.

 

[Dthomas3523]

How many rounds on barrel?

How many rounds since last cleaning?

 

[Zack_va248]

7115 FPS?


Ammo speed variations between lots totally happens
Without a true chrony speed it could be a few things.
[/QUOT
Typo I meant 2715

 

[Zack_va248]

How many rounds on barrel?

How many rounds since last cleaning?

About 1250 on the barrel. 150rds since cleaned. No copper solvent. Just carbon cleaning with a soft brush and wet patched for a patch or two. Then 5 dry patches until clean. Bartlein mtu 1:8 barrel for reference

 

[Deleted member 10043]

I guess I'm getting old. I follow the bullet and make the appropriate adjustments without much thought other than it is not unusual. I don't go damn they are going faster today, WTF? Especially, if it is still shooting good.

 

[Off Duty Ninja]

Get a chrono.

 

[Zack_va248]

I guess I'm getting old. I follow the bullet and make the appropriate adjustments without much thought other than it is not unusual. I don't go damn they are going faster today, WTF? Especially, if it is still shooting good.

I also follow the bullet. I see every miss, and impact 200 and out. That’s how I knew something was up when I was half mil high. If I couldn’t spot misses I’d of never got on target. Knowing what the bullet is going to do and guessing is the difference. “Know your dope” further verify everything. Especially if your trusting factories to produce a big piece of your systems accuracy. The fact it sped up this much isn’t a problem. Once I trued my dope I went first rd impacts ,dead on water line, from 300-700. Merely acknowledging something I haven’t seen over the last 10 cases of hornady 140g eldm. I understand 10 cases in the grand scheme of their ammo produced total is nothing but until this point I haven’t seen a mv deviation more than 15-20fps. Curious if anyone else has seen the same.

 

[Dthomas3523]

About 1250 on the barrel. 150rds since cleaned. No copper solvent. Just carbon cleaning with a soft brush and wet patched for a patch or two. Then 5 dry patches until clean. Bartlein mtu 1:8 barrel for reference

If it’s not a lot to lot variation, you may have a carbon ring.

Clean patches most of the time don’t equal an actually clean barrel.

 

[Underaverage]

If it’s not a lot to lot variation, you may have a carbon ring.

Clean patches most of the time don’t equal an actually clean barrel.

Except I was shooting the same lot of ammo as @Zack_va248 and I had a couple unexplained high fliers as well... So we saw the apparent velocity increase with more than 1 rifle system.

Obviously, we need a chrono to be 100% sure. But still.

 

[Dthomas3523]

Except I was shooting the same lot of ammo as @Zack_va248 and I had a couple unexplained high fliers as well... So we saw the apparent velocity increase with more than 1 rifle system.

Obviously, we need a chrono to be 100% sure. But still.

That’s why I said it could be a lot to lot variation.

 

[Underaverage]

That’s why I said it could be a lot to lot variation.

I completely understand lot to lot variation. That's to be expected. But the fact that we were getting apparent extreme variation all within the same lot that we were shooting is our issue. In addition to the fact that the dope we shot out and figured out via trial and error ourselves wasn't truing up with the 4dof app... It's mind boggling lol.