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

I've got a RRA in 458 SOCOM that is giving me problems. Feeding the first round out of a magazine causes the rifle to have light hits on the primer and a failure to fire. When the bolt is manually withdrawn, sometimes the round is extracted but, more often, the loaded round remains in the chamber. I've tried everything to get the initial round to slam home and function properly, but it's to no avail.

The reloaded ammo is checked with a chamber gauge and fits perfectly so it's being properly resized. Also, all subsequent rounds that self-feed from the magazine feed-fire-eject normally. Why is it that the first round just refuses to fully chamber and often doesn't have the extractor slip over the case rim?

Are you feeding the first round by with drawing the charging handle and releasing or by locking bolt to rear and dropping with bolt release?

Was thinking the same thing. Pulling the bolt all the way to the rear as apposed to releasing from bolt lock may solve the issue. This is what is happening with the subsequent rounds, gas is pushing the bolt all the way to "full stop" to the rear. May want to go for a heftier buffer spring?

Some chamberings,in some mags,are VERY fhuqking tight when topped off. Due same,the first round of a drum tight mag,takes significantly more ass to strip from feed lips,travel the ramp and get buried in the chamber. It is often "MAGICAL" to simply drive same,less that "extra" too tight round. Hint..................

Yep. That is the other reason I ran 29rds "down range". The other being that I could reliably hit a "Tac reload". Drum tight mags don't seat well against a closed bolt.

Yep. That is the other reason I ran 29rds "down range". The other being that I could reliably hit a "Tac reload". Drum tight mags don't seat well against a closed bolt.

If you download by one round, does the problem still happen?

The last time somebody mentioned this same problem they had 31 rounds in their msg (5.56).

I'm using 3 458 SOCOM rounds in a factory PM Mag-10 (.223) magazine. It could hold more. I have a NY compliant 458 mag that holds 10 (ordinarily holds 20 .223) which does the same thing when loaded with 3 rounds of 458.
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I've tried loading the first round both ways; bolt locked back with inserted mag then press bolt release button AND insert loaded mag with bolt closed and yanking the charging handle rearward and letting it go to achieve the maximum of forward bolt thrust. The fat ass rounds just don't cooperate.

When the extractor is not over the case rim, I would assume that the bolt isn't in full battery. But the rifle will drop the hammer which I thought couldn't happen when it's not in battery. I get very light hits but the hammer is dropping when I pull the trigger.

Does it have an O-ring around the extractor spring? If so remove it.

If memory serves me, it does have a tiny O ring there. I'll have to check. Isn't it needed?

It was added to the M4 carbine gassed guns. It’s become so notable that you’ll likely find one in every BCG out there. Except Colt, they came up with the idea but now use a proper 5 coil extractor spring.

There have been reports of problems occurring. Possibly an O-ring added to a proper strength spring won’t let the extractor snap over the case. Doubly so if your buffer spring is weak or buffer too light.
Similar to too much extractor tension on a 1911.

Mainly just throwing an idea out there.

For whatever it's worth, SOLGW BCG's do not have an O-ring.

That's good to know. Pretty sure my Sionics BCG didn't have an O-ring either but my newest Toolcraft did.

It's not always a bad thing but shows who's paying attention. And when paired with the right spring, it's not a bad deal but so many think that it has to be in there no matter which spring is in it. I've got some HD spring kits from BCM which are I believe Springco from years back that have the O-ring and supposedly the 5 coil spring but at the time, it wasn't known to be a bad thing. I've got a few from Colt that just include the 5 coil copper colored spring and black insert.

Maybe your chamber is out of spec.

Some will have an insert inside the spring, so with have the O-ring on the outside of the spring, some will have both.
Best practice is considered to have one or the other, but usually not both.

Best practice is to have a good spring and no O-ring.

I’ve never seen a kit without the insert. Blue for rifle gas and black for carbine. The O-ring was only meant for carbine gassed guns with the old spring.

I've been shooting and reloading for 40+ years but I'm rather new to the AR platform. I grabbed an AR before the nice governor outlawed them here in NY.
I shoot fairly stout loads (but within specs) and wouldn't mind trying a heavier buffer spring. I'm using a full factory RRA 458 SOCOM upper on a factory RRA Predator Pursuit (.223) rifle.
What would the next stiffer spring be? Where should I order one?

Assuming your lower has a carbine length buffer tube, if you want to try a heavier buffer spring, Sprinco makes an extra power one.


https://www.primaryarms.com/sprinco-m4-ar15-carbine-red-extra-power-carbine-buffer-spring

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.