243 Heavy Bolt Lift

[Recko555]

Hello,
Just got to breaking in my new rifle. It is a straight 243 (.100" freebore), 30" brux 1:7 twist (.236 bore), PTG trued Remington single shot action, and PTG bolt.
I have only had time to shoot 1 shot:
New Lapua Brass
BR2 Primer
45.0 H-1000
110 Smk
Jumped .010"

It was hard to open after this shot (never experienced this before in any rifle). The primer might of looked a little flat, but no crater or ejector Mark. Slight shine around primer. It was hard to close on the 1 piece of fired brass. New brass no issue.
So I am thinking I just need to back off the powder charge (didn't think 45.0 was going to be hot). Probably too much pressure with the fast twist barrel and tight bore.
Just wondering of any other ideas. Thanks.

 

[JBT47]

Solvent left in the chamber from cleaning can cause this issue as well.

 

[jr600yd]

Did you FL size the new brass prior to loading?

 

[K22]

Get some factory ammo and shoot it. If it works fine then it's your reloads. Reload issues I'd check:

1.Case sizing. What's the change in case head space from an unfired to fired condition. A case gage or Hornady head space tool can be used to evaluate.

2. Powder charge.

3. COL (.010 you reported should be fine, just double check your measurements. Bullet ogive can vary but normally not that much)

Hard bolt lift definitely needs to be investigated since it's one the sure signs of too much pressure. Primers flatness is not a reliable indicator. Ejection marks on the case is another sure sign of too much pressure.

 

[swd]

Back the load down enough to do a barrel break in. I have seen primers pretty flat for the first 6-10 rounds and then as the throat breaks in the pressure drops considerably. You may be able to get back up there just don't kill your brass in the first few shots.

 

[Recko555]

I do not FL new brass, but do straighten the case mouths with mandrel and then chamfer and debur.
I checked how clean the chamber was and it came out a little moist. So that is a possibility.
I brought the load down to 43.0 grains and increased jump to .020". Forgot to check case size of fired vs new brass. Will do that tomorrow.
Going to do a couple more shots tomorrow (life is busy right now).
Appreciate the info guys.

 

[Zero333]

Did you shoot only 1 time with the 45gr load ? or more than once and had hard bolt lift every time with 45 gr ?

If you shot the 45gr load only once and have other cartridges loaded at 45 gr, I recommend taking a few apart to verify they contain exactly 45 gr.

 

[Recko555]

I only shot one. Took apart other ammo and checked powder charge , they were all 45.0 grains.

I shot one with 43.0 grains H1000 with .020" jump, no heavy bolt lift. I will use this charge until barrel break in is done and then start increasing powder charge.