Home Forums Hunting & Shooting AR and Tactical Rifles Failure to fire

I've got to check on my factory spring length. I don't know if RRA uses a "carbine" or "rifle" length spring in their .223 Predator Pursuit.

Thanks for the link.

This place sells extra power springs for both carbine and a2 stocks.

https://www.griffinarmament.com/ar-556-308-buffer-springs-extra-power-15/

If it has a non adjustable A2 stock on it then it has a rifle buffer and spring. You won’t need the O-ring and probably no other changes either.

Just try it without the O-ring. Changing one thing at a time will keep us all from getting off track.

The great thing about the AR is all the consumer replaceable parts and “upgrades”.

But it’s also the biggest downside about the AR. Learn the system first.

OK I pulled the BCG and removed the tiny O-ring that is around the extractor spring. I'll shoot it next week to see if that helps.

FWIW - the rifle has a Rogers Super Stock with a 10" buffer spring.

Rogers stock is an adjustable carbine stock, meaning you can adjust the length of pull, with a carbine buffer tube (receiver extension). The spring is on it's way out as just over 10" is minimum OAL, 11.5" or so is max. It'll use a carbine buffer, if it's not marked on the face, it's as light as they make, they are marked H, H2 and H3. Then of course there are 9mm buffers both solid and reciprocating weights that weigh more.

But for now carry on without any other changes and see what if any difference it makes.

Any opinion on the Geissle Super 42 buffer and spring combo?

I’m not up on the 458 so I don’t know what you need. I use 223/5.56 in all my AR’s and use standard springs and H buffer for rifle gas, H2 for mid length and H3 for carbine gassed guns.

I like Geissele triggers but have not used much else from them. Springco is probably where I would look. Give them a call and see what they recommend.

When it comes to the 375/458 Socom, mags make a world of difference. CMMG or Tromix modified Lancer mags are the gold standard by which to judge all the others.

No oring on the extractor, standard buffer, buffer spring and no need to run an adjustable gas block unless you are running a suppressor

458 Socom forums has a wealth of information.

Curious what the feed ramp looks like on the RRA barrel extension. Is it one wide ramp missing the bottom lug or the majority of the lug?

FWIW - I do have/use a Lancer - NY compliant - 10 round SOCOM magazine with a center feed follower. However, the problem noted in my original post happens with this mag too. At the bench I typically use a Magpul 10 that holds 4 rounds IIRC but I only load 4 into the mag.

I removed the tiny O-ring from around the extractor spring an noticed that it is much easier to manually move the extractor. I'll give tis a try before experimenting with a 15% increased power spring. I did notice that Sprinco mentions using their 25% increased power spring with some cartridges, including the 458 SOCOM.

Taking another look at my buffer spring, I see that it is about 1/16" short of 10" and suspect that this may be adding to or causing the problem.

For a bolt rifle shooter, this AR stuff is like starting the learning curve all over again.

TWR - you were OTM (on the money). I removed the tiny O-ring and had the chance to shoot the rifle today. Not only did the BCG visibly move forward faster and smoother but the problem was 100% eliminated. Regardless of how I charged the rifle, it performed perfectly.

Thanks for all the helpful feedback everyone.

I get lucky now and then...

Glad it worked out for you.

Good job TWR. I'm sure the op is a happy camper. Good to have guys like you here to help some of us with AR issues. Luckily all of mine have ran like tops.

Just an update:

I shot the rifle quite a bit yesterday, testing with old brass, new brass, bullets of various weights and everything feed, fired & extracted perfectly. I dropped in a SpringCo power spring (15%) to see if anything changed. I did notice that the spring was about an inch longer. Everything worked the same and I couldn't really detect any difference.

I did notice that my brass ejects at a forward angle of between 1 o'clock and 2 o'clock. Does that indicate anything that should be addressed in the 458SOCOM?

Just to confirm, this gun has an adjustable carbine stock, correct?

If so and with you saying you run hotter ammo, then I’d say a heavier buffer could be beneficial. In the past I’ve skipped the H3 and used a 9mm buffer (which is the heaviest carbine buffer) for some oddball calibers that were higher pressure.

But it could be as simple as an ejector spring that needs trimming.

When you inspected your fired brass, did you notice any pulled rims or shiny marks from the extractor? The only thing that requires attention if a gun is ejecting at 2:00 is if it is pulling the case out before it has fully dropped pressure and released its hold on the chamber wall.

Yes, the rifle wears a Rogers adjustable stock. There are no pulled rims or shiny marks from the extractor.
I'll assume that the new +15% spring may add a millisecond of delay in the bolt opening. It certainly didn't hurt anything. As I stated above, SpringCo recommends a +25% power spring for the SOCOM. But since the factory spring, which was about 1/8" short of minimum still worked well, I didn't want to go up 2 steps in spring tension.

The SpringCo +15% was bought in combination with a new extractor spring. I assume that it's just stiffer but I haven't installed it yet.