Short Stroke
- Thread starter martiy
- Start date
The gas tube issue you had would not affect failures to feed when manually cycling the weapon.
What mags do you have?
When does it occur? Whole mag, or just first/last rounds?
Are the mags seating correctly?
What ammo are you using? Have you tried different ammo?
Did you assemble it from parts, or just throw in the BCG and drop a fully assembled upper onto a fully assembled lower?
Regards.
Mark
What mags do you have?
When does it occur? Whole mag, or just first/last rounds?
Are the mags seating correctly?
What ammo are you using? Have you tried different ammo?
Did you assemble it from parts, or just throw in the BCG and drop a fully assembled upper onto a fully assembled lower?
Regards.
Mark
I have only experienced these exact symptoms while using some problematic LAR 15 10 rounder mags when loaded to 10 rounds.
With any other mags my LMT would function flawlessly. BTW, those problematic LAR mags once fixed also function fine.
With any other mags my LMT would function flawlessly. BTW, those problematic LAR mags once fixed also function fine.
I am using the factory LMT mag
Jams happen anytime
Mags are seated correctly
Using Winchester 223 ammo (haven't tried others)
The lower was brand new fully assembled from a 12.5" LMT Piston that I had (MRP I think). The fully assembled upper is a LMT 10.5" I bought off CGN. I added a LMT FA BCG from Questar.
Clearly, LMT makes crappy AR parts (just kidding).
I'm going to assume you did not mate a non-M4 profile barrel extension to an M4 upper receiver? If so, that could be your problem.
I will check the feed ramps and maybe post a pic
Clearly, LMT makes crappy AR parts (just kidding).
I'm going to assume you did not mate a non-M4 profile barrel extension to an M4 upper receiver? If so, that could be your problem.
The feed ramps look like the top right pic so should be ok.
You probably have tried it, does it happen with PMags too?
Clobbersauras
CGN Ultra frequent flyer
- Location
- Waaay out west.
This probably has nothing to do with your problem, but what weight buffer are you running?
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If the lower was originally from a 12.5" piston MRP then it has an H2 buffer... Combine that with underpowered .223 ammo instead of 5.56nato and this could explain your problems. Hard to tell without seeing the gun but start there.
Mark
Mark
Bolivar
CGN Ultra frequent flyer
I think Easy is looking at whether the ammo you are using is hollow point or not. HP can cause feed issues in some rifles. Try a different brand of ammo that does not have HP bullets?
However, that does not explain a failure to pick up a round from the chamber when manually cycling. When in fails this way, does the bolt ride right over top of the cartridge or start to pick it up and then looses it when the bullet tip jams against the receiver/barrel extension.
Regardless, my thought is that perhaps there a problem with your mag. Beg, borrow, buy another mag and see if the same problem occurs.
However, that does not explain a failure to pick up a round from the chamber when manually cycling. When in fails this way, does the bolt ride right over top of the cartridge or start to pick it up and then looses it when the bullet tip jams against the receiver/barrel extension.
Regardless, my thought is that perhaps there a problem with your mag. Beg, borrow, buy another mag and see if the same problem occurs.
The H2 buffer could for sure cause CYCLING issues, (short stroking) but not when manual feeding.
This has to be a mag issue if manual feeding is jamming. Maybe poor choice of ammo combined with a bad mag?
As for H2 buffers, I typically use those in DI shorties. A piston gun probably just needs a standard buffer, no?
This has to be a mag issue if manual feeding is jamming. Maybe poor choice of ammo combined with a bad mag?
As for H2 buffers, I typically use those in DI shorties. A piston gun probably just needs a standard buffer, no?
I was thinking more along the lines of the Winchester 45 grain stuff being made for varmint shooting in bolt guns and their bullet crimp isn't very tight. When used in semi-autos like AR15s, the bullet may get set back into the case a bit much while going into battery causing feed issues and a possible disaster.
Use nothing less than the WIN 55 grain fodder in an AR. With shorter barrels, hotter ammunition is desirable to keep the gun running in proper time.
Use nothing less than the WIN 55 grain fodder in an AR. With shorter barrels, hotter ammunition is desirable to keep the gun running in proper time.
i have tried 4 or 5 different mags and still the same.
No hollow points, Just Winchester 55 gr ammo
When charging the bolt will just ride right over the round and not budge it. When it jams it actually picks up a round and it jams with the bolt open and usually dents the neck of the cartridge.
As I said I did get an H2 buffer fut I dont think I changed the spring, could that cause short stroking?
Clobbersauras
CGN Ultra frequent flyer
- Location
- Waaay out west.
Is there a chance your receiver extension (buffer tube) is dented or bent so that it doesn't allow full travel of the bolt when you charge it? It sounds like the bolt is not cycling far enough back to pick up a round.
You might want to try a standard buffer as well if you intend on using the same ammo.
