Bolt resistance when closing on some rounds?

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ReedTX

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Hello all,

Over the weekend I visited the range with a forum member and shot my first reloads, everything went well and I was happy with my group.

Today I have reloaded another 10 .308 rounds and have used the same trim length 2.005 and same COAL 2.735. All the rounds chamber and the bolt locks, but I did notice that some offer some slight resistance on closing the bolt. The resistance is only slight and the bolt can still be closed with just my thumb and fore finger.

Are these rounds safe to fire?

Why did this happen, did I mess up the full length sizing process? It is odd that only some rounds are effected out of the small batch I made.

Thanks

Reed.
 
Test your sizing operation on a few batches of brass before you load them. I put a sharpy line on my die so I know exact where I was and I can clock small adjustments. This is also important when trying to lock the ring. If you tighten the lock when the die is set it will lock it in place which is bad unless you are using bushings.
 
Had a great time with you at the range Reed. Looking forward to doing it again.

Dumb question, have you cleaned your chamber since shooting? I didn't get a look at your cases to see if they were sooty. I just checked the one case to see if your primer was flattened.

You could mark one of the cases in question with a Sharpie and look for any rub marks after chambering. Probably as troy fairweather said, just a matter of bumping the shoulder back a bit.

Reed had a fantastic grouping for his first reloads. He said he was nervous shooting the first one. I counted, 10 fingers and two eyes after shooting. He did well.
 
Just a thought - have you cleaned the bolt lately? Sometimes the extractor pivot point (or spring) gets gummy, needs a bit more of a push to snap over the rim.

Of course, this only happens in a push-feed rifle, or a single-loaded controlled feed. On a magazine loaded controlled feed rifle, the cartridge comes up under the extractor automatically...
 
Generally this happens when firing brass previously fired in a different rifle, especially one with generous headspace. If you find brass fired in an M99 or Ishapore SMLE, expect this a lot. The cure is full-crush resizing. If you notice when adjusting your sizing die without a case inserted, there is a little bit of slop at the top of the ram stroke. Your dies advise to adjust this down until the slop goes away. Now when you try it with a lubed case inserted, you'll notice some of that slop coming back into play. A bit more down on your sizing die will be required. You want the full cam-over leverage and full insertion into the sizing die to line up. Different headstamps of brass can alter this dead-stop point slightly, as can dinged up case rims or heads extracted by certain military semi-automatic rifles.

Another 2 causes that ARE potentially dangerous are too-long COL and too-long cases. The bullet is entering the leade of the rifling and contacting the lands. This can spike pressure in a hurry, and will be indicated by engraving on your bullet upon extraction. In severe cases, the bullet may stay in the barrel! Double check your COL and make sure it is reasonable. Another potential cause is too long brass. The mouth of the case is contacting the point of restriction in your chamber behind the leade. This can also result in pressure spikes mimicking a severe crimp. This scenario is uncommon unless brass is extremely long as most firearms have some safety margin here. Double check your trim length after FL resizing.
 
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If different headstamps it could just be a slight variation in the makeup of the brass. It could also be more than once fired and need to be annealed, or most likely you just need to adjust your die down a little to size more. Some brass is slightly thicker or harder and has different amounts of springback and if you don’t anneal you may just sort them into batches and size each batch appropriately.
 
dartor said:
Reed had a fantastic grouping for his first reloads. He said he was nervous shooting the first one. I counted, 10 fingers and two eyes after shooting. He did well.
Click to expand...

I shot my first reloads with my left hand lol. I figured if something went wrong and I blew something up, I would still have my normal shooting hand, lol.

Welcome to the addiction.
 
Congratulations on successfully reloading and firing! After all these years, during load development, I still pull that trigger with a bit of trepidation.
While most likely a FL sizing problem, there are several reasons a bolt can be a bit tight. Mark the case with a sharpie to determine where it’s tight and go from there. Don’t assume it’s just a FL issue.
By any chance do you have a case gauge? Good luck.
 
ReedTX said:
. . . did notice that some offer some slight resistance on closing the bolt. The resistance is only slight and the bolt can still be closed with just my thumb and fore finger.
Click to expand...
Yes, they're fine.

You are feeling just a bit of interaction between sizing and chamber. Add a smidge of sizing (screw the die down just a little), and it should go away.
 
What probably happen was the brass work hardened from the last firing, that prevented it from moving the shoulder back as before. This is a normal when working with brass. The next time you size the brass you may need to lower your crimp die by 0.002" to over come the difference. Or if you decide to anneal, you may have to back off the sizing die since you eliminated the spring back. Even changing lubes can impact how much the brass moves, as well as dwell time. With dwell time being the pause when the brass is fully embedded/inserted into the sizing die.

As is you have what I would consider best for brass life. Minimal working is a good thing.
 
If it’s only some, it might be a process problem. Some necks could be lubed sufficiently and others not.

Bolt resistance in and of it self isn’t always a problem, some of us set dies that way.



That said, that will make all of the cases have very slight compression as the bolt is closed, not just some.

“Some” rounds with clearance in the chamber and others without, assuming complete strokes were made and die settings were not altered, would suggest to me that your expander is pulling the neck and attached shoulder out as you pull it back out of the case.

Polish the expander, lube inside the neck, you can even remove it all together, just to see if you get more consistent results. If everything is better with no expander, that confirms where the problem is.
 
Thank you all for all your responses. The bolt and chamber appear to be clean, I will do the sharpie trick later and report back.

Perhaps I did not run the handle enough on some of the brass during the resize, this would explain why some fit perfectly and others offer a little resistance. I did go and resize some more brass and was able to recreate the issue when I did not run the handle the entire way down. Lesson learnt!

For the poster asking I am shooting a Ruger M77 Mk2.

I have loaded more cartridges with different charges inline with Dartors advice, I am excited to get back out there and see how they shoot!
 
If your OAL and trim length is correct , then your sizing die is correctly adjusted if you feel slight resistance on bolt closing. You can turn it in just a hair if the bolt resistance bothers you, but you’ll work your brass more.
It is a good idea to chamber a few, then eject and check for engraving, or use the sharpie method
 
twarr1 said:
If your OAL and trim length is correct , then your sizing die is correctly adjusted if you feel slight resistance on bolt closing. You can turn it in just a hair if the bolt resistance bothers you, but you’ll work your brass more.
It is a good idea to chamber a few, then eject and check for engraving, or use the sharpie method
Click to expand...
I might clarify, by sizing excessively you’re working your brass more than necessary not just when it’s sized but when it’s fired as well. If you’re using the ammo in the same gun you need to just size it enough to go back in that particular chamber.
With the proliferation of semi-autos it’s become common to crush the shoulder back so far it’ll fit in any chamber. And keep in mind, the die manufacturers need their dies to work acceptably for the greatest number of buyers. Not necessarily what works best for your particular rifle. This is evident in their die adjustment instructions. You have to find the best setting for your gun.
 
ReedTX said:
Hello all,

Why did this happen, did I mess up the full length sizing process? It is odd that only some rounds are effected out of the small batch I made.
Click to expand...
Some brass will spring back more than others, particularly if you're using mixed headstamps and/or you're using brass that has been fired previously and different amounts. The more you work your brass it can become "work hardened" and will resist sizing, and will spring back more.

For my Garands, I find about 30% of my FL sized cases from the same headstamp and fired the same number of times will require another trip through the sizing die with it screwed down a tad more, in order to pass the case gauge test.

Annealing your brass will help, but it's a PITA.

For bolt actions, you don't NEED to FL size, though some smart people suggest you should, and you don't need to bump the shoulder back more than a thou or two clearance to enable the bolt to close easily. And if you need to add a little more effort to close the bolt, it's not dangerous, just a bit annoying. If it fits, it ships. ;)
 
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