Community for Kel-Tec Shooters banner
1 - 20 of 37 Posts

·
Registered
Joined
·
101 Posts
Discussion Starter · #1 ·
I think I have solved my over gassing problem. I've been fighting this ever since I got my RFB. After getting it back from Kel-tec with new gas and barrel everything except Prefecta and American Eagle .308 150 gn was over gassed. All 7.62 were over gassed. Talked to Kel-tec and tech told me that I should be in the B+8 range for 7.62. I was over gassed with cap almost off. Piston was still very tight after many trips to range. I removed the 3 gas rings on piston. Now all 308's and 7.62's are in the B+7 to 10 range. Now I'll try my suppressor and see how it works. Before I was B+25 with .308 and now around B+9. Still think it will be over gassed at B+ 40, but it's worth a try.
 

·
Registered
Joined
·
1,416 Posts
That was one of the reasons I liked the piston with ring concept. It allowed user non-permanent "tuning" of the system beyond the adjustment available from the vent cap...
 

·
Registered
Joined
·
113 Posts
I think I have solved my over gassing problem. I've been fighting this ever since I got my RFB. After getting it back from Kel-tec with new gas and barrel everything except Prefecta and American Eagle .308 150 gn was over gassed. All 7.62 were over gassed. Talked to Kel-tec and tech told me that I should be in the B+8 range for 7.62. I was over gassed with cap almost off. Piston was still very tight after many trips to range. I removed the 3 gas rings on piston. Now all 308's and 7.62's are in the B+7 to 10 range. Now I'll try my suppressor and see how it works. Before I was B+25 with .308 and now around B+9. Still think it will be over gassed at B+ 40, but it's worth a try.

I have 250 rounds through mine and I can take the gas knob completely off and the bolt will lock back on any ammo I try. I have the knob set at B+41 just so I won't lose the cap. I lined the gaps in the three gas rings up thinking it may bleed off more gas but I have not tried it yet.

I think I will remove the gas rings completely as you have and see if I can get it to lock back in the B+5 to B+25 range. That will certainly prolong the life of the buffer, bolt, etc.
 

·
Registered
Joined
·
113 Posts
I removed the three stainless gas rings from my piston and now I can adjust the gas for particular rounds for the first time. Shooting 147gr PMC .308 (which I have a bunch of) my adjustment is perfect at B+16.
 

·
Registered
Joined
·
86 Posts
I have T0790 and am way overgassed with a suppressor.

I will be calling KT when they open up to see what fix is needed.

The suppressor piston says it's only for Gen 2 gas systems, which mine is not.

So I don't know how I fix my Gen 1 gun?
 

·
Registered
Joined
·
1,416 Posts
The gen1 piston used sealing snap-rings(from an AR gas system). You should be able to fairly easilly experiment with removing those to try and tune the piston for the supressor...
 

·
Registered
Joined
·
1,416 Posts
Which time? :)

The first time was when they went from the 1st gen piston to the 2nd gen. The 2nd gen piston is WAY easier to machine. I guess they thought they could get fancy and do away with the pistons and use the machined discs of the new design to provide enough resistance and gas bypass.

One thing I have noted since the 2nd gen came out is a little less consistent gas system performance and the seemingly endless string of folks who had issues adjusting the gas system per the manual. Also note the several different 2nd gen piston designs that have emerged, I am assuming to attempt to control this issue. Now it appears that the rings have been re-introduced on the 2nd gen piston(yet another variant) in a similar attempt.
 

·
Registered
Joined
·
1,416 Posts
So I will NOT be able to install teh Gen 2 piston in my gun?

But I should be able to remove or file down the Gen 1 rings?
Correct on both. The first and second gen gas pistons are completely different and NOT interchangeable. Post a pic of your piston so we can be sure on that if you like. The biggest giveaway is that you have to rotate the 1st gen piston about 30 degrees to unlock it from the gas block. The second gen just pulls right out after the carrier is removed...

The rings used on the first gen are from the AR gas system, so anyone who has AR parts(probably just about every gunsmith in the US) should have replacements for you, should you need them...
 

·
Registered
Joined
·
86 Posts
Everyone keeps mentioning "rings" but I just took the darned thing off, and there was only ONE ring!?!

It was a yuuuge ***** to remove too!

So since I could't remove only one or two, I took the single triple wound ring off. I am going to have a hell of a time putting it on. I'll see if standard AR-15 rings will go on.

As far as the piston, yes it came out with a rotation, but it was a 60 degree twist, as per my manual.


-

So I guess I see what results I get suppressed with zero rings and a reinstalled adjustment knob.

Is that too much porting I wonder?
Even with a can?
 

·
Registered
Joined
·
86 Posts
Removed the SINGLE gas ring (really long). Fired gun with no gas rings at all.

Locked the bolt with suppressor on with minimal gas setting.

Would not lock it with suppressor off even fully maxed setting.

Gotta install 1 or 2 rings and retry. Looks like I will be overgassing to some degree, but I can't have it both ways, apparently.
 

·
Premium Member
Joined
·
15,000 Posts
Just took mine apart, it is brand new just arriving from kel-tec. It has 3 rings.
Purchased directly from the factory? Or from a dealer/FFL or online?

It makes a difference, it may have been made months (or years) ago...sitting on a shelf somewhere.
 

·
Registered
Joined
·
53 Posts
texcl2, that serial is newer than mine and I have one of the Gen 2's with no rings. Could you post a pic of the piston so we can get a look? There are quiet a few people here that have been helping trouble shoot gas issues (I have benefited from many of them) and if there is a new piston out in the wild that will make things much more interesting... I mean complex... for diagnosing problems.
 
1 - 20 of 37 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top