Hello all, I’ve been a longtime lurker but joined up so I could post a question about my 11.5" AR, I’ll try to follow the format about technical issues as much as possible:
What make and manufacture is your AR? Spikes lower with CMMG 2 stage trigger, spikes 11.5 ST-15 upper (carbine length gas system). AIM Surplus NiB BCG and PRI gas buster CH.
2. What modifications were made prior to actually shooting it: Only major mod other than listed above is the Spikes ST-T2 heavy buffer
3. What type of ammunition did you use? This is the part that gets weird. It only cycles the crappy steel cased Tula .223. It has been 100% with over 500 rounds, not a single malfunction. I tried shooting some CBC 77 gr OTM 5.56, and it was about 75% reliable, literally every 4th round would FTE (see pic). With winchester 5.56 it would FTE about every 6th or 7th round.
5. Were modifications made to the gas port? None that I know of
6. Take a good picture of the part or problem in question. Sometimes a picture is worth a thousand words. See below
Just wondering if anyone has heard of a rifle not cycling brass cased 5.56, but will cycle steel .223? Thanks for any info!
Take out the ST-T2 and try a real buffer before anything else and see how it runs. The ST-T2 is known to cause issues. Also check your gas key and see it it loose, check your gas rings, and your gas block as well unless it’s a FSB style.
Sorry haven’t been able to test it with the carbine buffer yet. To answer you extractor question, it’s an AIM Surplus NiB BCG and they have this to say about their extractor:
“When installing the extractor to the bolt, a crane-o-ring is inserted with the spring to insure proper ejection.”
Well I don’t have an H2 buffer, anyone recommend a good place to get one that won’t break the bank? A regular carbine buffer on my last range trip had the same result, lots of FTE. I emailed Spikes and they weren’t much help, I’d expect that a factory spikes upper would run 5.56 but I guess having it only run .223 is acceptable to them.
I would just get one from BCM. As the weight of the buffer goes up so does the price because of the use of Tungsten weights in heavier buffers (or that’s my understanding anyway).
I say something is up with the BCG. Not sure why your case will not eject off the face of the bolt, as the picture shows its extracting off chamber of barrel. If it’s a buffer issue, then you need a heavier buffer than a T2 weight.
sounds over gassed to me as well. IIRC the spikes weight is between a carbine and H2. Heavier should solve the issue. If not, report back. I expected the same results with the carbine buffer.
The ST-2 is a great upgrade for a CAR buffer… and still not as useful as an H-Buffer, especially for overgassed stuff. I have one rifle where the ST2 works brilliantly, and it’s primarily because it was intended to be under-gassed and ran with a lighter semi bolt carrier and the ST2 means I can feed that thing junkier ammo and only get intermittent problems.
Everything else, H2 (or A5H3, especially on SBR’s).
You haven’t done anything wrong, it’s just a tolerance stack of Spike’s trying to design around maximizing reliability for users who want to run really junky ammunition with a menagerie of parts - and both your buffer and upper are designed to compensate for that with the result when combined being a really overgassed SBR with too little reciprocating mass. H2’s are cheap (compared to anything else that would fix it completely really cheap), that should fix it - an H3 might be an ideal answer, but those cost more and are harder to find.
Huh, I hadn’t thought about NiB BCG reducing friction, therefore decreasing the gas required and making an already overgassed gun more overgassed. That’s a good thing to keep in mind.
I had bad luck with a Spikes barrel. It was 5.45x39 but the bore was 5.56, so it keyholed at 25yd. After dozens of emails and calls, I eventually gave up and decided I’d just post about it a lot on the internet.
When was this? I have a Spike’s 5.45 upper and it’s never had an issue with accuracy. I know they discontinued the 5.45 now though.
Only issue I had was with a FN CHF barrel from Spikes that needed quite a bit of rear windage to zero. They had that swapped out and back to me in 2 days.
Early last year. I started a thread on CalGuns asking for suggestions, bore diameter was mentioned, I slugged it and got around .219 (I think) when spec is .214 (again, I think… this was a while ago). The measurement I got was right for a 5.56 gun, but the chamber was for 5.45.
I bought it pre-owned but supposedly un-used, but they didn’t say that was a problem… they were just too much of a hassle for too long for it to be worth it. They didn’t have any numbers regarding correct bore diameter, I had to find one, then he didn’t believe that one so I had to find another one, then he didn’t get back to me for weeks, etc. Had he just said “sorry, it’s used so no warranty” that would have been a much better response than what happened. The result was horrible customer service, not responding to emails for weeks, until I called and said he was still waiting on numbers.
I understand that most of their stuff is supposed to be pretty good, but I won’t buy any of it again.
Take a good look at the gas tube where it goes into the gas key.
I recently bought a used Noveske 10.5" CHF barrel which had a worn out gas tube.
I replaced the gas tube and all went back to normal.
The diameter at the tip of the gas tube should be around 0.179"
