Remington 700 Firing Issue

[ESBVader]

I have a Remington 700 (Remage setup) in .308 with a recently trued action by LRI along with a 26" Criterion 1/10 barrel and a Jewel HVR trigger running suppressed. Since I received the rifle back from LRI, I put the action in an AICS AX Chassis.

For ammo I am running Lapua brass, Federal 210M primers, IMR 4064 powder, and Sierra 175 SMK's set to .010 off the lands. I have verified my shoulder bump lengths, headspace, and OGIVE length with the loads I am using. (Over and over again to make sure.) I check and double check my powder load as well. The below image is of a ladder test I ran today starting with 42.1 grains and moving up .2 grains to 44.1. My velocities didn't look crazy high (see data below) when chronographed and there were no pressure signs on the case (unless you include of course the pierced primer...)

I had not previously tested it with the original 20" barrel so I can't say with any certainty that this had happened before.

I am trying to find my velocity nodes and have the issue below with the primers being pierced in some cases and, in three others, the primers not firing at all even though they are dimpled.

Before I send my action off to LRI again to have a look and possibly doing something about a firing pin bushing, which is the only thing I can think of that may need to be done, does anyone have experience with the issue below?

 

[ESBVader]

Just ran across this and wondering if it's contributed to what I am experiencing?

"A weak firing pin spring can guarantee a pierced primer, not a balancing act but the pressure on the firing pin must be greater than the pressure inside the primer/case. When the pressure is greater inside the case/primer the pressure pushes the firing pin back, when the firing pin is pushed back ‘far enough?’ the dent in the primer becomes a hole, and that is when the hot, high pressure, metal cutting gas cuts the face of the bolt around the firing pin hole."

Talked to a gunsmith and he mentioned that with the number of pierced primers I have that I've begun to anneal my firing pin spring, which will only make things worse going forward.

I am thinking that a firing pin bushing, new spring, and possibly a new firing pin may help to solve the problem... I think...

 

[Scotts556]

Try a new spring first. that is something you can do at home.

Scott

 

[sinister]

I'd have to agree. Your primers all seem to still have nice radii in their pockets and no raised cratering around the pin impact point.

Start with a new spring, maybe a new firing pin as well (if you're using an OEM pin try a Tubb Speed Lock).

 

[Gunfighter14e2]

A new firing pin spring that is much above the std 18# std spring will do that. I had some weak spring an replace all 4 with wolf 28# springs. 3 of them started doing that right out of the gate, one did not. I inspected everything. the one that did not was dragging internally, polished it up an it did it as well. Replaced them all with Wolf 18# an every one now works perfect.
Lesson for me was if a std spring will not work it's either weak, or there's an issue that needs corrected. All my old springs were 8-10 years old, (an those guns get shot a lot) I now change all mine every two years no matter what. It's my understanding bench rest guys change theirs every year.

 

[lockedandloaded]

Have you done any kind of primer pocket uniforming?

 

[XLR308]

I would have stopped after the first couple of blanked primers but that's me.
It also looks like you do have some cratering and a few of the cases look like there was brass flow into the ejection plunger.

Just curious but the ones that you had light strikes on were those after all of the blanked primers or before ?

 

[DAVETOOLEY]

You didn't say whether the firing pin hole was bushed. It takes excessive pressure for your system to pierce that many primers. Clean the internals of your bolt then shoot a box of factory ammo just for the hell of it. I'm very surprised you didn't kill your Jewell trigger. They usually break when firing pins moves to the rear after piercing a primer.

 

[ESBVader]

I would have stopped after the first couple of blanked primers but that's me.
It also looks like you do have some cratering and a few of the cases look like there was brass flow into the ejection plunger.

Just curious but the ones that you had light strikes on were those after all of the blanked primers or before ?

I know it's a bit ridiculous, but I actually didn't notice they were doing this till 3/4 of the way through when I stopped to pick up my brass. Definitely won't be doing that again.

The ejector marks were from a previous load test in a different gun where I was really pushing too hard. I think I only had one ejector mark produced from this batch at my on one of the highest powder loads. (44.1 grains I think...)

The light strikes were happening after several of the punctured primers towards the end of my "fail" session... lol

 

[ESBVader]

You didn't say whether the firing pin hole was bushed. It takes excessive pressure for your system to pierce that many primers. Clean the internals of your bolt then shoot a box of factory ammo just for the hell of it. I'm very surprised you didn't kill your Jewell trigger. They usually break when firing pins moves to the rear after piercing a primer.

The firing pin hole was not previously bushed. I just sent the bolt off to LRI to have that done the other day following that session. Also am going to replace the firing pin, since there was flash cutting occurring, as well as the firing pin spring. I've confirmed that it was actually a weak firing pin spring that was causing the issue. The more I shot, the more the spring became weak through annealing. The loads were in the middle to light range for the most part. 41.9 - 43.5, with a few in the higher range, but the strikes were even happening at 41.9. Verified headspace and distance to lands as well.

As far as the Jewell trigger, I actually had to take it completely apart twice and clean it, though there were no signs of debris. The main spring inside the trigger was bent. After fixing that, it ran like a charm again.