I'm sure some of you saw my other thread about how I was having problems loading to the proper oal. That is fixed but a new problem arised. What's happening is my rounds are very hard to close and open the bolt on. I fired exactly one round at the range then decided I didn't want to go forcing anything. My initial thought was that possibly the necks were too tight. Upon some measuring, I don't think that is the case. The neck od od a completed round is right at .273. The od of the fired case measures. 276 so theres obviously room for the necks to expand. The bolt closes just fine on a new unloaded piece of brass, but not on s completed round. The chamber is criterions 6mm creedmoor match. The load was alpha brass, 41.5 grains of h4350, and a 107 smk seated to 2.775 ( 20 thou off the lands). Chambering a loaded round is extremely hard, but there are no marks on the case anywhere. The bolt was very hard open on the fired round also. The primer was fairly flattened and theres a bit of a brass imprint on the bolt face. Is it possible that the load isn't necessarily too hot, but the hard chambering problem is creating extra pressure and skewing me load results? Yes, I know I probably should start lighter and work up but I saw a lot of recommendations for that load so I thought I'd try it. Besides a possible neck thickness issue, which it doesn't seem to be to me, I'm at a loss of what else to think. I'm hoping it's something simple so I can get shooting already. Any ideas? Any pics are measurements you might need to help me I'd be happy to post up. Thank you
- Thread starter Mauser48
- Start date
I would think it has to be either the bullet hitting the lands or stuffing the neck in the chamber if an unloaded case will chamber easily. Primer isn’t sticking out is it?
Primer is flush. I just looked again at the reamer used to chamber the barrel and it is for a .277 neck so that shouldn't be an issue. Another thing interesting I remembered is that I had the ejector and cocking assembly out of the bullet while I was checking my oal, and at 2.775 the bolt would drop freely on the case with a seated bullet and no issues. Once the ejector and cocking assembly were put in them that became a different story.
What action?
Stock 700 short action, no truing or anything done to it.
Can you step us through what brass you are using and your reloading steps?
Brass was brand new alpha and all the case necks were round so I didn't run it through the sizer die. I primed the cases, chamfered and deburred the necks to avoid shaving the bullet jacket, trickle charged to my desired charge, then seated the bullet to 2.775 in a hornady standard bullet seating die. No crimp.
Take a bullet or other pointed tool and make sure you can depress the ejector all the way below the bolt face fairly easily.
Seat the bullet a little deeper and try again. That will at least tell you if that’s what is binding. That would explain unexpected overpressure as well. If you are measuring case to tip with no ejector to get your lands you could have a couple of errors stacking up.
Since you mentioned a cBI barrel, I wonder if you set headspace on the tight side?
I’d test the brass to see if your brass needs the shoulder bumped back at all. If the unloaded chase chambers fine then you can rule that out and look at the bullet.
This is super easy to test, you’ll need to strip the striker and ejector from bolt. Then just insert a piece of brass. The bolt should close on its own weight. If it doesn’t you may need to bump the shoulder back slightly.
I’d test the brass to see if your brass needs the shoulder bumped back at all. If the unloaded chase chambers fine then you can rule that out and look at the bullet.
This is super easy to test, you’ll need to strip the striker and ejector from bolt. Then just insert a piece of brass. The bolt should close on its own weight. If it doesn’t you may need to bump the shoulder back slightly.
Yep it was closing on it's own weight. I have to say, I feel like an idiot now. I just went out and pushed the ejector a few times to see if it would go down all the way and it did. I then tried chambering the cartridges I loaded and they were all fine. Not nearly as hard as before. I'm thinking maybe the ejector was a little kinked up?
