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Hard bolt Lift
- Thread starter martyj
- Start date
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RockyMtnMT
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Has the velocity changed?
Hummer70
Member
Several things may be going on with your rifle.
1. is it new and fired very little?
2. is the bolt hard to lift when chamber is empty?
3. on the ammo you are using does the bolt close easily or do you have to force it down to close the bolt?
If the rifle is new make sure it is unloaded and just cycle the action with the trigger taped to the rear so it does not sear up.
After about 500 actuations look closely at the bolt looking for shiny spots. Pay particular attention to the back of the locking lugs to see if there is equal contact on all lugs. If only one is shiny get some lapping compound and place it on the shiny lug and continue to work the action until the other lugs shows contact.
4. Check your ammo with a micrometer and measure the bottom of the case .200" up from the bottom of the case before and after firing the case.
5. Also measure the diameter of a new unfired round and and see how much expansion you have. Unless the rifle is set up for long range accuracy with a custom reamer the fired necks can be .002"to .005".
6 Check to see if your fired case is too long.
7. You could have a die problem. Had a friend who could not resize 300 Win Mag in his rifle and he wound up buying two more sets of dies and still could not get bolt to close. I checked it, unscrewed the barrel and set it back two threads and rechambered it with my match reamer and the fired cases went in just fine. The factory reamer was not machined right.
1. is it new and fired very little?
2. is the bolt hard to lift when chamber is empty?
3. on the ammo you are using does the bolt close easily or do you have to force it down to close the bolt?
If the rifle is new make sure it is unloaded and just cycle the action with the trigger taped to the rear so it does not sear up.
After about 500 actuations look closely at the bolt looking for shiny spots. Pay particular attention to the back of the locking lugs to see if there is equal contact on all lugs. If only one is shiny get some lapping compound and place it on the shiny lug and continue to work the action until the other lugs shows contact.
4. Check your ammo with a micrometer and measure the bottom of the case .200" up from the bottom of the case before and after firing the case.
5. Also measure the diameter of a new unfired round and and see how much expansion you have. Unless the rifle is set up for long range accuracy with a custom reamer the fired necks can be .002"to .005".
6 Check to see if your fired case is too long.
7. You could have a die problem. Had a friend who could not resize 300 Win Mag in his rifle and he wound up buying two more sets of dies and still could not get bolt to close. I checked it, unscrewed the barrel and set it back two threads and rechambered it with my match reamer and the fired cases went in just fine. The factory reamer was not machined right.
Kevin P McNeilly
Well-Known Member
Everyone has said what is probably going to work for you but I'm gonna say also check for carbon ring with that retumbo. It will cause pressure spikes.
DLJ6
Well-Known Member
Will a fired case Re-chamber?
Harry Knutz
Well-Known Member
This^^^^
If you cant slide a projectile into a FIRED case with little to no resistance, The necks are too tight. If you just necked the brass down and then shot it without neck turning or reaming, You are going to increase pressure and it will cause the bolt to feel sticky after firing.
Without neck turning, There is not enough clearance for the neck to expand when it fires, Another clue is increased seating pressure on fired cases.
BrentM
Well-Known Member
Everyone is pretty much saying it, brass issue. Might tell us what process you use to resize the cases and what you use to measure oal, shoulder bump, and neck before and after firing. I doubt it's a neck issue but you won't know until you dig into the case measurements. Make sure you have good calipers and a good case overall length gauge or a case gauge like found a Wilson case gauge. I prefer calipers and hornady gauges but a Wilson works too.
Make sure you clean your chamber. Retumbo is dirty as heck and if you run a suppressor you'll need to clean often. Carbon builds up fairly fast and can create a tighter neck area falsely with carbon build up, and it doesn't take much. I bought a boretech chamber cleaning kit and it makes short work of it. Worth every penny
Make sure you clean your chamber. Retumbo is dirty as heck and if you run a suppressor you'll need to clean often. Carbon builds up fairly fast and can create a tighter neck area falsely with carbon build up, and it doesn't take much. I bought a boretech chamber cleaning kit and it makes short work of it. Worth every penny
With new brass that is not fireformed it is sized to fit all SAMMI chambers. So that means on the small size so it will fit even small chambers. When you fire new brass in a chamber it will take some of the pressure to push the brass out to fit your chamber. Next firing that energy will not be used to fireform the brass and and it will show as slightly over pressure. We are talking close to max loads here. If you are at starting loads you should not see pressure either way.
Lefty7mmstw
Well-Known Member
I think Keven has a very valid point. The slower burners like Retumbo are rather dirty. I've had trouble with carbon deposits on a couple of my overbore 7mm's. These rifles don't take well to the patch only crew or nylon brush crew. You've got to actually scrub to get this fouling out.
Brass may be a bit of an issue too but we aren't talking about a small cartridge here. The energy used to blow the brass out isn't going to make or break a load unless you are past point of sanity already. If he can get a pill in fired brass he's probably fine; if not a neck turning is in order.
Brass may be a bit of an issue too but we aren't talking about a small cartridge here. The energy used to blow the brass out isn't going to make or break a load unless you are past point of sanity already. If he can get a pill in fired brass he's probably fine; if not a neck turning is in order.
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Full size and ^^^^^^^^^^^^^^^
Rob L.
Well-Known Member
I've found on my hard to extract cases that the base has expanded.
I presume you are resizing and trimming to length? Some dies, even full length sometimes don't reduce the case base enough. Neck sizing will not for sure.
I'll bet if you mic the base of cases that fit you'll find the ones that don't fit are at least a thousand's or two larger in diameter.
Rob-
I presume you are resizing and trimming to length? Some dies, even full length sometimes don't reduce the case base enough. Neck sizing will not for sure.
I'll bet if you mic the base of cases that fit you'll find the ones that don't fit are at least a thousand's or two larger in diameter.
Rob-
LRHWAL
Well-Known Member
I would do a bunch of measuring and try to narrow things down like that. You have to measure things to know things in reloading, the rest is guessing.
The very first and most simple thing I would do would be to make sure that the length of a sized case is within spec for your chamber. It would seem like the first place to start and don't recall seeing it suggested. If the brass has flowed and the case needs trimming it can pinch the projectile and not release it. This can happen from the very first reload. This seems to me like the most likely reason. You can just trim to spec and test fire, or measure your chamber length with a little insert sold by Sinclair and others that fits into a case to measure where your neck length stops. You could just trim to the length of the virgin and check.
Do you size the virgin brass before loading, or seat straight into the case neck? Your neck tension with the sized brass may be excessive. Again you can measure to check.
Another thing would be to make sure that a bullet drops into a fired case - i.e. no doughnut and most likely not a too tight neck. It would seem strange that the neck dimensions would change aside from forming a doughnut. Measure the outside neck diameter of the ammo loaded with virgin brass and your reloads in fired brass. That should tell you if something changed. Also whilst shooting the 1x fired brass shoot some virgin brass loads at the same time - this should help tell you if you have a carbon build up causing you issues, as that should be a problem with both.
Test firing would be a good idea with loads at lower levels it seems.
You may have mentioned it and I may have missed it, but I assume all of the other components remained the same, same bullets, same seating depth, same primers and powder lot number etc. If not you have introduced a bunch of other variables to check out.
Check out one thing at a time.
The very first and most simple thing I would do would be to make sure that the length of a sized case is within spec for your chamber. It would seem like the first place to start and don't recall seeing it suggested. If the brass has flowed and the case needs trimming it can pinch the projectile and not release it. This can happen from the very first reload. This seems to me like the most likely reason. You can just trim to spec and test fire, or measure your chamber length with a little insert sold by Sinclair and others that fits into a case to measure where your neck length stops. You could just trim to the length of the virgin and check.
Do you size the virgin brass before loading, or seat straight into the case neck? Your neck tension with the sized brass may be excessive. Again you can measure to check.
Another thing would be to make sure that a bullet drops into a fired case - i.e. no doughnut and most likely not a too tight neck. It would seem strange that the neck dimensions would change aside from forming a doughnut. Measure the outside neck diameter of the ammo loaded with virgin brass and your reloads in fired brass. That should tell you if something changed. Also whilst shooting the 1x fired brass shoot some virgin brass loads at the same time - this should help tell you if you have a carbon build up causing you issues, as that should be a problem with both.
Test firing would be a good idea with loads at lower levels it seems.
You may have mentioned it and I may have missed it, but I assume all of the other components remained the same, same bullets, same seating depth, same primers and powder lot number etc. If not you have introduced a bunch of other variables to check out.
Check out one thing at a time.
