Not an expert reloader, but not total newbie either. I have a problem with Lapua .308 brass necked down for my SPS Varmint 7mm-08. It's hard to close bolt on loaded rounds. I have one of the Callahan Speedloc's in the bolt. I wondered if it just made it feel harder to close due to heavier firing pin spring? Remington 7mm-08 brass does not seem to cause any issues, although maybe somewhat slightly heavy bolt close. I used a Sharpie on the case necks of the Lapua brass and don't see any marks left when testing a loaded round. When a live round of Lapua is fired in the gun it doesn't seem to be any harder to open the bolt than it was to close it. Although it's way to stiff and unacceptable to me closing and opening. I'm at a loss of what might be the issue?
- Thread starter longbow62
- Start date
Mike the neck of a loaded round several times around the circumference and note the measurements. Fire that round and mike the neck again. If you don't have a minimum of .001 expansion then you have neck diameter interference. Even .001 is extremely close, bench rest close and not really practical or desirable in any application except bench rest. I assume that you have already full lenght sized some cases to eliminate shoulder-body to chamber interference.
Have you confirmed the length of the case after you neck it down?
I had this issue necking down 257 Bob cases for my 6mm Rem.
I had to shave a little brass off.
I had this issue necking down 257 Bob cases for my 6mm Rem.
I had to shave a little brass off.
How far down have you adjusted your sizing die? I had the same issue when making .17FB brass from .221FB and ended up having to turn the die down much tighter than I would have ever imagined. Hope this helps.
Sounds like headspace....check the shoulders
How does the bolt feel without a loaded round? Firing pin spring tension would be the same with or without a round. I would guess you either need to bump the shoulder, round is loaded long (you will see throat contact on the bullet) or the body of the brass needs to be taken in a bit. If you have a cleaned and polished round, you should be able to see where the problem areas are after you cycle the round a few times, inspect the round and see where its hanging up.
Kirk Roberts
Kirk Roberts
Mark the case and bullet with a sharpie. Chamber and look it over for scuff marks. This will show where it is too tight.
This just reminded me of something important.
I have similar issues, and my F/L die is already set up to contact the (Dillon RL550B) base plate. I haven't mic'd my case lengths yet, but I have suspicions about my brass being overlong in the neck.
I just took a moment and ordered a Lyman Case gage from Amazon, which should simplify this matter. It should arrive Tuesday and I think it's well worth the price of $21 and change including shipping.
Greg
I have similar issues, and my F/L die is already set up to contact the (Dillon RL550B) base plate. I haven't mic'd my case lengths yet, but I have suspicions about my brass being overlong in the neck.
I just took a moment and ordered a Lyman Case gage from Amazon, which should simplify this matter. It should arrive Tuesday and I think it's well worth the price of $21 and change including shipping.
Greg
I had a problem similar to this until I started annealing every time. It seemed the bolt would close after sizing, but let it set for a week and the bolt would not close. As the brass work hardened it would develop a memory. You can even feel the difference between an annealed case and one that has been fired several times when you size them.
Probably a combination of not bumping shoulder back enough and not turning nks. My br rig chamber is set up so that loaded rds are 2 thou under chamber nk dimension. If u are measuring with dial caliper then the measurements might be alot tighter then u think. I turn nks to .312" loaded, it won't take long and will help improve ur reloads as much as annealing .
Bump back the shoulder 0.002 and see how that helps. 0.001 of shoulder bump as you're saying is on the tighter side. A bump of 0.002 or even 0.003 may make all the difference in the world.
Curious, how many times has this lot of brass been fired?
Curious, how many times has this lot of brass been fired?
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