10.5" SBR - Buffer and Buffer Spring Options

[Cold_Bore_88]

I know this is usually a forum dedicated to long range shooting but I had a questions I wanted to throw up. My SBR is a Seekins 10.5". It will cycle 62 GR M855 very well. It will cycle anything with a suppressor.

I had an issue when it came to some old .223 I found. FTF every shot. I know that it is a lighter charge but I would like my SBR to cycle anything. I have a crappy spring and buffer at present. Any advice on a combination of a spring and buffer you would recommend? Looking at a Wolf spring and H buffer. Problem is, which wolf spring?

 

[earthtrekker1775]

As long as the spring is good quality and new you should be alright. I use a Spike's Tactical ST-T2 Heavy Buffer with a Brownells Chrome Silicone M4 Buffer Spring (078-000-087W). I am running a pieced together 10.5" with a noveske barrel and carbine length gas. It runs like a fine clock with any variety of ammo I feed it (currently around 400 rounds since last cleaning). If you have pistol length gas you will have to wait on others to chime in.

Lower Parts - Spike's ST-T2 Heavy Buffer T2 Buffer [SLA00T2] - $37.95 : Spikes Tactical

AR-15/M16 BUFFER SPRINGS | Brownells

 

[DirtyRod]

I run a standard spring and carbine buffer on both my 10.5" and 11.5" rifles. Both cycle factory and my reloads. They both worked with Spikes H2 buffers as well.

 

[mercracing]

I run a Spikes T-3 extra heavy buffer and a Wolf extra power spring.

 

[leid]

Howdy OP,
Been using Colt carbines since the '70s. Virtually every 10.0"/10.3"/10.5"/11.5"/14.5" factory barrel I have fired to date is overgassed so they will cycle reliably in all expected conditions even with low pressure .223 pressure loadings. So I have to slow down the cyclic rate by using heavier buffers especially when firing suppressed. The one exception is a Noveske 10.5" barrel with a SwitchBlock which works extremely well suppressed or unsuppressed with the SwitchBlock set to the proper position. Most of the short barrels I get to use are Colt, LMT, or Noveske. I don't know anything about Seekins but you should ask them how to set up your carbine with their 10.5" barrel. They drilled the gas port and hopefully have a good idea of what works well with their gas port size. Most all the short barrels I use will work 100% with anything from a standard carbine buffer to an H3 or 3 piece 9MM buffer when used with a standard Colt carbine spring on semi or auto. The one exception is a Colt 14.5" M4A1 SOCOM barrel; it will function correctly on semi with a standard carbine buffer but needs at least an H buffer to function correctly on auto due to bolt bounce. And these carbines will fire anything from .223 pressure PMC to 5.56MM pressure BHA MK 262 MOD 1 with 100% reliability. HTH

 

[groundhogbuster]

Every 10.5" I have ever fired, were perfect, but they were all LMT. Sounds like it is undergassed, so if you are running an H just swap it out for a CAR. Is it a pistol? The reason I asked is that most 10.5"ers always seem to be "overgassed" if anything, and run perfect with an H1, H2, H3 buffers. Need to know if it's a CAR gas tube or a Pistol though.

 

[biggin69]

My RRA SBR with 10.5" barrel came with a standard CAR spring but an H3 buffer. It seems to feed just fine with everything from Wolf 55gr to my handloads with 77gr SMK.

 

[Cold_Bore_88]

Every 10.5" I have ever fired, were perfect, but they were all LMT. Sounds like it is undergassed, so if you are running an H just swap it out for a CAR. Is it a pistol? The reason I asked is that most 10.5"ers always seem to be "overgassed" if anything, and run perfect with an H1, H2, H3 buffers. Need to know if it's a CAR gas tube or a Pistol though.

It is a Carbine length gas system. It is not a pistol.

It has the Seekins gas block. I have it all the way open.

 

[groundhogbuster]

It is a Carbine length gas system. It is not a pistol.

It has the Seekins gas block. I have it all the way open.

That's a good thing, see what buffer you are using. Just look at the front of it and see if it has an H1,H2, or what. If it does, try a regular CAR buffer. If you put it together, make sure your gas block is perfectly aligned with the gas port. Just a tad off, and you're not getting enough gas. To make this easier, put a level on your flat top, and make sure the gb is level with the top rail. Also if your going to handload for a 10.5" you may need to raise your load a tad, since the commercial ammo is running ok.