What kind of problems would you see if there wasn't enough neck clearance in your rifle. Been having trouble getting my new gun to shoot consistently. Keep getting fliers 1-2" inches off from the rest of the groups at 100 years and load in not consistent from 1 !day to the next. I started measuring the brass and found that a bullet will not go back into the neck of a fired piece of brass. Neck diameter of a fired piece is only .001 larger than sized brass. I thought about turning the necks down .001 per side and see if that helped. Could this be a cause of my problems?
- Thread starter jsthntn247
- Start date
What kind of chamber?
How many times has the brass been fired?
What kind of dies are you using?
What tools are you using to measure re-sizing (headspace) and seating depth?
Are you using the "right" powders/primers/bullets for the cartridge? Source of data?
Have you loaded for this chambering before? How about other chamberings?
I could add another dozen questions that need to be answered before any reply would be more than a WAG.
How many times has the brass been fired?
What kind of dies are you using?
What tools are you using to measure re-sizing (headspace) and seating depth?
Are you using the "right" powders/primers/bullets for the cartridge? Source of data?
Have you loaded for this chambering before? How about other chamberings?
I could add another dozen questions that need to be answered before any reply would be more than a WAG.
If your measurements are accurate, I think you are on the right track to at least address one issue...it may well be the one causing your accuracy problems. The fact that a bullet won't slip into a fired case is a good clue., in itself. I'd turn a few necks, just as you mentioned, and go test again. Are you getting any pressure signs? Pressures can go extremely high if no/ not enough clearance is present.
I just ordered a mandrel for my neck turner, going to turn the necks .002 and see if it helps.
I don't think it's clearance. I have a .30BR that runs a neck clearance of .001" on the diameter. Shoots really well.
Can you slip a bullet into a fired case....An inch is "almost" as good as a mile here. Too much clearance is simply working the brass more.
No, I cannot fit a bullet back into a fired case. But it still shoots very well. That said, running that tight a neck is careful business. I wouldn't do it if it weren't a benchrest rig.
Somewhere between .001 and .006 of clearance, the brass is allowed to expand and stay expanded, because I can fit the bullets in back in the case of my other rifle with .006 clearance (6mm, though, so not exactly apples to apples). Both are great shooters - I would look elsewhere for the flyer, but turning another thou of the necks doesn't sound like a terrible idea.
I just looked at it again. I can't force a bullet in the neck any. Sized diameter is .306 (.002 tension) fired is .307. This is a hunting rig also.
Do you know what the clearance is between the neck and chamber? It sounds like you are probably running it pretty tight, especially for a field rig. If so, I'd turn a little more off the brass to give a little breathing room.
No not sure if the specs on the reamer used. But not much undoubtedly, lol
Are you chamfering the inside and out side of the case .You might have a burr on the inside of the mouth causing it to be tight right at the opening. Your cases might be too long and the neck could be squeezing down at the mouth .
I would find out. Maybe even worth a cerrosafe cast. For safety's sake I'd check that out, and make sure you have at least .003". I sort of doubt it's the cause of your flyers, but if it's really tight it could be. I wish more smiths would stamp the neck diameter on the barrel.
