Blown primers are a pressure sign unless it is a mechanical issue
Firing pin appears to be piercing primer
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Fierce Carbon Rival rifle.
MagnumManiac
Well-Known Member
Firstly, it is VERY rare for a pierced/blanked primer to be a mechanical issue with the firearm. It is nearly always excessive pressure that causes pierced primers.
Secondly, if you haven't taken that bolt apart and cleaned it thoroughly and blown 100psi+ air pressure down it, there may be blanked pieces inside your bolt between the firing pin and bolt body…guess what this often does? Pierces every other primer, if you don't clean it, eventually you will have fail to fire issues.
As someone that worked on Target rifles, I saw this enough to know that often, I had to use an awl to remove those blanked peaces because the firing pin is flattening them into the bolt body and they conform to the shape of the internals…
Cheers
Secondly, if you haven't taken that bolt apart and cleaned it thoroughly and blown 100psi+ air pressure down it, there may be blanked pieces inside your bolt between the firing pin and bolt body…guess what this often does? Pierces every other primer, if you don't clean it, eventually you will have fail to fire issues.
As someone that worked on Target rifles, I saw this enough to know that often, I had to use an awl to remove those blanked peaces because the firing pin is flattening them into the bolt body and they conform to the shape of the internals…
Cheers
So appears the consensus seems to be that the issue is over pressure vs firing pin piercing the primer from misalignment, etc.
I typically work off of the Hodgdon ( I typically only use powders that are reflected in their online data) load data and always start low and work up. This is my first time to have any primer issues, other than slight flattening on hottest end loads during load development. Admittedly, I am a very amateur reloader, so learn something every day.
I will take the rifle to my gunsmith and have him inspect and repair bolt/firing pin assembly before shooting anymore with this rifle. Also have him inspect the damaged primers to hopefully determine the issue.
Worst part, not really, is that there is the best node so far at the 42.5 load
I typically work off of the Hodgdon ( I typically only use powders that are reflected in their online data) load data and always start low and work up. This is my first time to have any primer issues, other than slight flattening on hottest end loads during load development. Admittedly, I am a very amateur reloader, so learn something every day.
I will take the rifle to my gunsmith and have him inspect and repair bolt/firing pin assembly before shooting anymore with this rifle. Also have him inspect the damaged primers to hopefully determine the issue.
Worst part, not really, is that there is the best node so far at the 42.5 load
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Yup, I've had to clear out pieces before due to blown primers. I was 100% due from op. More like excessive back pressure.
MagnumManiac
Well-Known Member
I forgot to add this, sorry.
To do a quick test on your bolt assembly, uncock it, measure firing pin protrusion, it should be .045"-.055" for proper function. Maximum protrusion should not be more than .065".
If it measures shorter than .045", then it is possible you have blanked sections stopping your pin going all the way forward, this is what causes more pierced primers because the primer flows into the firing pin hole.
Cheers.
To do a quick test on your bolt assembly, uncock it, measure firing pin protrusion, it should be .045"-.055" for proper function. Maximum protrusion should not be more than .065".
If it measures shorter than .045", then it is possible you have blanked sections stopping your pin going all the way forward, this is what causes more pierced primers because the primer flows into the firing pin hole.
Cheers.
RegionRat
Well-Known Member
BTW, in addition to all the advice folks have already added, just letting you know that from now on... Primer Blanking is considered a possible pressure sign. You have to investigate further to classify the root cause.
You will want to follow that advice to search for the potential shrapnel inside the bolt body as @MagnumManiac is advising, or get help if you don't have the background. The firing pin tip should be closely inspected under magnification and by feel to make sure it hasn't been damaged.
cohunt
Well-Known Member
Hmmm
I had forgotten that the magnum small rifle primers were made. Was informed of that earlier in this thread.
Most likely an issue with overpressure or your Firing Pin. Should not have punctured the Primer. Unless they are bad primers.
CCI # 41 are very hard cup primers designed not to have "Slam Fires" in AR style rifles/pistols. We use them in our ARs..
Buy Mil-Spec No.41/5.56 Primer | 1
Shopping for the Mil-Spec No.41/5.56 Primer - Learn more about the latest Standard Rifle/Pistol Primer and other hunting or shooting gear at CCI.
I had this precise issue and it was an slight overpressure issue exacerbated by a firing pin that needed to be bushed. I simply fired the load in two other rifles with no pierced primers but the velocity was pretty high considering what the max should have been. I'd owned this rifle for over 10 years and had experienced NO issues with any primer irregularities and I'm pretty anal at inspection of fired brass and primers.
My vote is for both issues. Both the firing pin that needs to be bushed and possible/probable overpressure. Consider soft primers possibly contributing to the issue too.
I suggest you get a few friends to fire that load in their rifles if possible and see if the primers pierce. They might be reluctant to fire those loads in their rifles but that would be a pretty definitive test.
Also, regardless of the outcome of the tests, it would be very advisable to disassemble the bolt and do a thorough cleaning in an ultrasonic cleaning machine and reassemble with checking for specs on size and firing pin extension beyond the bolt face.
BTW... That precise same load has been my go to load for varmint hunting in other rifles now and I'm always looking for primer piercing or cratering and so far no issues.
Just one man's opinion garnered by 50+ years of shooting and handloading.
My vote is for both issues. Both the firing pin that needs to be bushed and possible/probable overpressure. Consider soft primers possibly contributing to the issue too.
I suggest you get a few friends to fire that load in their rifles if possible and see if the primers pierce. They might be reluctant to fire those loads in their rifles but that would be a pretty definitive test.
Also, regardless of the outcome of the tests, it would be very advisable to disassemble the bolt and do a thorough cleaning in an ultrasonic cleaning machine and reassemble with checking for specs on size and firing pin extension beyond the bolt face.
BTW... That precise same load has been my go to load for varmint hunting in other rifles now and I'm always looking for primer piercing or cratering and so far no issues.
Just one man's opinion garnered by 50+ years of shooting and handloading.
ncwg2boatguy
Well-Known Member
CCI450 are small rifle magnum primers, also BR primers have thicker cups too.
ncwg2boatguy
Well-Known Member
If it puntures #41 primers it needs to go to a smith for sureMost likely an issue with overpressure or your Firing Pin. Should not have punctured the Primer. Unless they are bad primers.
CCI # 41 are very hard cup primers designed not to have "Slam Fires" in AR style rifles/pistols. We use them in our ARs..
Buy Mil-Spec No.41/5.56 Primer | 1
Shopping for the Mil-Spec No.41/5.56 Primer - Learn more about the latest Standard Rifle/Pistol Primer and other hunting or shooting gear at CCI.www.cci-ammunition.com
marshalldodge
Active Member
6CM needs the CCI450
I learned that lesson years ago in my 6x47L, and haven't had issues since switching to the 450.
I learned that lesson years ago in my 6x47L, and haven't had issues since switching to the 450.
