SR 25 ECC Gas ring cycling questions etc.

[Lethrneck-03]

Ok well I’m new here I just got into the longer range rigs and the wanting to shoot further. So I went and got me an KAC ECC sunk some money in it and it won’t shoot M80 Magtech nor will it run Winchester service grade 175 Sierra Match King BTHP but it shot the hell outta Hornady 168 gr. black.
Alright so it fails the bolt test with the gas ring nor supporting the BC Weight. With the M80 and Win ammo it FTF FTE double feeds etc.
But was spot on with the 168 H Black ammo well I bought a field repair kit for the gas ring so thinking that’s the issue because am I wrong to say this pig should eat anything I put in it?

The gas key is staked checked it
The block is pinned
It was lubed up liberally til it’s running outta the rear of receiver
Stock KAC buffer and spring
KAC Mags black follower

Short stroking = gas or ammo issue?

I’ve been reading some old threads about this here and all say send it to KAC but don’t want to go that route at all since it shot the 168 gr. fine.

Am I wrong to think this rifle is only going to shoot 168gr.?

And has anyone changed gas ring? I’ve changed them out on AR15s Is it the same to swap them out? I really don’t want to jack a new ring up forcing it to go on since well ya know to get a ring you gotta buy the kit which I don’t want to spend another 332.00$ just for another ring.

Thanks in advance just for some up to date insight on these rifle and why or what could be going on.

 

[mtrmn]

If you have the 1-piece ring, it will fail to hold up the bolt carrier every time.That test basically only applies to an AR15 with 3 gas rings. The large frame bolt carrier is much heavier and the 3-piece rings will probably fail as well.
When you oil it up, you have to get the oil inside the BCG where the gas ring{s} is/are.

 

[LRRPF52]

Every KAC SR-25 I’ve had come through courses shot very well, but they are much less common than a lot of other rifles so my data is somewhat anecdotal. They have all shot 175gr SMK and Hornady 178gr extremely well, even out to 1000yds.

KAC is normally very good with QC, but some will slip through with any company.

Look in your FCG and see if there is noticeable soot from gas leakage.

 

[Lethrneck-03]

Copy that CLP the bolt quite well before I shot. I was thinking that as heavy as that BC is that the test was probably for an AR 15 BCG. Well at least I now have a repair if needed.the rifle was new old stock so Imwas wondering how in world could the gas ring be shot already.

 

[Lethrneck-03]

There is some on it yes. The 178 gr worked better than the M80 to a point but still the same. It’s definitely under gassed I think. I’m leaving the BCG locked back on the spring maybe some constant compression on it will lighten up the action a little Maybe lighter buffer H2 ? I looked around for a KAC H2 but all,say run what came in it the 21057 PN

 

[Jsp556]

Where’d ya find a NOS ECC?

 

[TheOE800]

There is some on it yes. The 178 gr worked better than the M80 to a point but still the same. It’s definitely under gassed I think. I’m leaving the BCG locked back on the spring maybe some constant compression on it will lighten up the action a little Maybe lighter buffer H2 ? I looked around for a KAC H2 but all,say run what came in it the 21057 PN

I have seen ECCs with gas block alignment issues, typically if they’ve been taken apart for cosmetic surgery.

 

[Lethrneck-03]

Alright love the rifle and yes It had some cerakote put on but had nothing to do with what the problem was.

I really like to figure stuff out and so I’ve been fooling with it since I last posted. So here’s what I did and finally had some good results.

Long story short

Fooled with gas tube and block, different ammo, new gas tube, All kids of different ammo, CLP, etc. etc. I think the KAC mag I have is from 2014 it’s in good shape but the rounds when the bolt grabs one it half pulls another out. And the bolt still won’t lock on it either. I plan on buying another KAC mag when I can find one.
Til then I am rocking the Magpul mag the SR15s come standard with PMAGs so that says some thing to me.

1) Dunked BCG Buffer and spring in 5W 20 oil put into rifle.
2) M80 Win ball into KAC Mag
3) Rifle ejected perfect but failed to lock back twice.
4) Bought a SR25 M110 P Mag and everything is like clockwork. Locks back on 1 round for 5 times so it’s cured I’m assuming.

Couple hundred bucks in parts ammo etc I would have never thought motor oil was needed and a non KAC mag being I grew up on CLP for maintaining rifles.

Felt good shooting through 45 degree angle sights watching rounds fly and feeling that bolt lock back last round.

 

[Quietguy88]

It sounds like a gas issue. Weigh the bcg and buffer? If it was receiving proper gas, an 18oz bcg and 6oz buffer would cycle fine with any proper m80.


I have a rubber city armory bcg, hosting a McFarland gasring and it fails that ring test when clean and dry. Lube makes it slide super smooth.

However, just to go through the initials.. does the gas tube terminate at the center of cam bolt pocket in upper receiver? The bcg travels rear of the bolt catch roughly 3/8" when cycled by hand?

I had a poorly manufactured gas tube.... It shrouded the gas port by 50%. Cause cycling issues that I could not find. For months. Eventually, the gas block came off. I looked through the gas block port into the gas tube. Saw it was off. I used a drill bit and opened up the gas tube to match the gas block. Problem fixed.

I have no experience with KAC. They are just too damn Gucci money for me. My full on mega maten with proprietary handguard is expensive enough...... So, I dunno anything about all them Knights parts.. but if the only thing to cycle that action is super hot loaded bolt action ammunition.... You either have mechanical short stroking, or gas starvation short stroking.

Got signs of physical restriction? Funny wear marks? Lack of travel? Not proper length parts? If not... That gas block or gas port in barrel is the first bet.. are those gas blocks hard to remove from kac barrels? If not.. get a visual and correct as needed.

 

[bfoosh006]

How many approximate rounds have been fired through the KAC ?

Maybe a little more break in , needed ?