Thread: Light Primer Strikes

ok so thinking left field here....if folks have in past managed (with dire consequences) to fire a .308 round in .270 chamber!!!!!!! does the rim held in bolt face hold it firm enough to allow primer ignition??? or does case need to enguage at shoulder......
if the rim holding is enough....it rules out the extra shortcase/long chamber senario......

looking forward to hearing how you get on with fresh primers.....Im hearing reports of multiple failures on clay targets at gunclubs,sometimes up to 5 misfires across 10 shooters or more......anyone else confirm this is actually happening???

My Bergara sometimes fails to fire. I'm using CCI LR primers. Recocking and firing a second time they go off. The strange thing is it has only happened on the subsonic rounds, even though I use the same primers and cases in the supersonic rounds.

Greg Duley testfired one of the single shot break opens a few years back....if not closed firmly,it would misfire 50% of the time.....consistantly...... BILs bakail did it from new too,simple fix for gunsmith once I worked out what was going on....which is sort of what was aid before re is the bolt closing completely....

Originally Posted by Sideshow

See if he has different brass too.
Try some factory rounds that way you can take the rifle out of the equation.

Good idea cheers!

Hey sorry just saw I was tagged in this post. I had 280ai and loaded for it. I've got a new box of Hornady 162gr factory 280ai ammo here that you could try. I've had light strikes before in 338 and changed primers and fixed it (after trying different brass, firing pin etc).
But if you want to try the factory ammo to see if that works ok, let me know. Cheers

Originally Posted by Jim356

Hi all,

Im having a problem with my Remington 700 doing light strikes on primers. I have just got my 280 AI up and running and was doing a ladder test when every 1in 5 rounds was not firing as the firing pin was not hitting hard/deep enough for ignition. I am using CCI 250 magnum primers as it was all I could get my hands on at the time with Peterson brass. I have done some testing around headspace and am confident that has nothing to do with the issue. Firing pin assembly looks cleaned with no gunk build up in it so can't see a major issue there. Firing pin assembly is a light weigh one supplied and installed by Gunworks.

With a few peaces of the brass that misfired I reprimed them making sure they were seated as deep as they could go to see if the firing pin was actually seating the primers further into the case. Off the 4 rounds 1 misfired again but I am not confident this is out of the equation.

I do have some federal gold match large rifle primers on the way to test as I have read that CCI primer are supposedly harder than the rest.

This is a new issue as I am not the first owner of this rifle. I had not shot this gun before getting it reamed into 280 AI but would imagine this problem only came about since I have owned this rifle.

Anyone have some suggestions of how to troubleshoot or where to go form here?

I was also using CCI when having light strikes and moved to Federal and not 1 since. I have federal Magnum primers here and maybe some LR primers too you can try if you want to

@Jim356 any progress bud??? I see Curtis has offered some help if needed,how did you get on with the problimatic rifle??

Originally Posted by Micky Duck

@Jim356 any progress bud??? I see Curtis has offered some help if needed,how did you get on with the problimatic rifle??

Hey Micky, Yep had some fed match primers turn op the other week. Probably shot 80 primers, some live rounds some not with 0 misfires. So seems like it was a easy fix at this stage! Just chasing speed now

good stuff....pleased you seem to be on top of it.... I cant recall if it was CCI primers I started out with,but I do remember swapping them out at same time I learnt to release tension off bolts for storage,I have used them again with zero issues so it could have been a combination of both.
I believe there is just about nothing, other than muzzle breaks ,or really heavy recoil,more likely to stuff up good shooting form and induce a flinch,than misfires,it puts a real dent in your confidence if you dont know if gun will fire....

Originally Posted by Micky Duck

good stuff....pleased you seem to be on top of it.... I cant recall if it was CCI primers I started out with,but I do remember swapping them out at same time I learnt to release tension off bolts for storage,I have used them again with zero issues so it could have been a combination of both.
I believe there is just about nothing, other than muzzle breaks ,or really heavy recoil,more likely to stuff up good shooting form and induce a flinch,than misfires,it puts a real dent in your confidence if you dont know if gun will fire....

I will defiantly second that

How far does your firing pin protrude when you relax the firing pin?

Can you measure the distance from the datum line to the bottom of the case on both a fired and resized case?

When you fireform you cases from 280 to ackley, does the bolt close with ease or do you feel a little bit of resistance?

Did you buy the gun as a 280AI or did you have it done?

Is the 280AI your first ackley'd rifle?

Make of it what you will, here is a link to a report on primer cups and their thicknesss. In summary all large rifle primers are .027 thou thick, with the possibilty of Military ones being thicker

Small rifle primers mostly are 0.020 thou to.025 thou with CCI BR4's being the thickest

Dont shoot the mesenger its info from the web and as such is subject to variables.

https://www.accurateshooter.com/tech...0%B3%20thick.)

Originally Posted by johnd

Make of it what you will, here is a link to a report on primer cups and their thicknesss. In summary all large rifle primers are .027 thou thick, with the possibilty of Military ones being thicker

Small rifle primers mostly are 0.020 thou to.025 thou with CCI BR4's being the thickest

Dont shoot the mesenger its info from the web and as such is subject to variables.

https://www.accurateshooter.com/tech...0%B3%20thick.)

Also a possibility that despite all being the same thickness, there may be differences in hardness.

@Jim356 When fire forming from standard non AI cases to Ackley I always struggled and pondered the question of 'what way is best'?
I read and tried all methods, dont know where you are at and you might be doing this already, but the following is the absolute best way:
Take a fired 280 or 3006 case you got from somewhere, neck size 2/3rds down the neck, then progressively turn the die down until the case just chambers with a firm bolt. Examine the case, it will have a small donut ring bulge near the base of the neck that is not sized. When the bolt is closed the case is held firm, camed between this bulge and the case head. Trim and chamfer etc and load with a moderate load, and go hunting. No cream of wheat, fast powder, kapoc and cast projectiles etc etc etc

Greetings All,
As mentioned previously in this thread light firing pin strike and missfires can be different to a lot of different things but it can be due to a combination of things. One thing that was mentioned by @Moa Hunter was excess head space, This can be present in the rifle or it can be created in the FL sizing die. The OP mentioned the .280 AI as the problem chambering. The .280 AI chamber is shorter from the neck shoulder junction than the parent .280 Rem case. This is done so factory .280 ammo can be fire formed in the AI chamber. To convert a .280 Rem chamber to .280 AI the barrel needs to be set back a thread so that his junction supports the case properly. This takes extra work and I don't know how often this step might be ommitted. All of the other 06 based cartridges have shorter headspace than the .280 so other cases need a false shoulder created to support the case close to the bolt face when firing.
Recently I bought myself a Hornady Head Space Comparator. Measurements revealed that my old Lyman 6.5x55 dies were setting back the shoulder more than 0.010" from the fired position in my T3 and more like 0.015" in my M38 and a friends Ruger 77. New Lapua cases measured close to fired cases in the T3 so the problem was the dies. A new set of Redding dies and a Competition Shellholder were purchased but I found the Redding dies still needed the +0.010 shellholder to get the right amount of shoulder bump. The US standard dimensions for the 6.5x55 clearly differ from the original. There is a level of arogance in the US about things not invented there and the same situation may apply to other continental cartridge dies so be warned.
Regards Grandpamac.