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Just bought my first ar pistol!!!! was playing around with it on (cheap tula ammo)and had some problems with FTExtract and im thinking this thing is a bit under gassed is there anything i should try to play around with before having the gas ports opened up??? and if not what size should i poen them up to???
Try brass ammo first. Then diagnose issue. Tula is steel, steel ammo is not always great.
I would strongly advise against opening up the gas port. Like Del said-dont shoot steel cased ammo in an AR. Brass casings will expand to the chamber and then shrink a touch, steel casings expand and are not as elastic. You will stick a case eventually.
Put at least 3-400 rounds through it before you pass any judgment on its reliability.
They are also a bit sensitive to your technique, make sure you are not "limp wristing" it.
Is this a factory complete pistol or a build? If it is factory whose is it?
Quote:
Originally Posted by BPTactical
factory dpms.......there is no way i wont shoot steel case if a gun doesnt shoot steel but will function with brass then it is barely working with brass imo..... all my other ar's only get a diet of steel
po put 100 rounds through it ive got like another 200 or so ill try shooting it some more but do you have any buffer weight/ spring combos i can try?\
why not open up the gas port???
its your AR, get out the uni-bit and open'r up.
My SBR has a Kitty kat 7 1/2in upper on it and it works great the way I got it, but I dont shoot steel case ammo out of it.
+1 on steel case ammo junking up an otherwise perfect gun. Many years ago I had an AR that always gave me extraction/ejection/cycling issues. Turns out when I quit trying to run the steel case stuff all of my problems magically disappeared. Needless to say, I now reserve the steel stuff to use in AK rifles.
But, do what you wish as it is your weapon. Over-gassing an AR by making the gas port too large will cause issues as well. If the chamber isn't chrome lined i would recommend doing some serious polishing of the chamber to start with and see if that helps.
Generally I prefer to eliminate variables when diagnosing an issue.
Ammo first. Opening up the gas port is a last step. In between fall springs and buffers
As mentioned over-gassing creates its own set of issues with number one attempting to open the bolt while chamber pressures are excessively high. Can you say sheared lugs and ripped off case heads?
Make sure the weapon is lubed well and keep it held as firmly as possible.
Is this a brand new pistol? If so contact DPMS. But they are going to yap at you for shooting steel cased ammo. Some warranties are even voided by steel case.
Steel cased ammo works in AK and SKS type firearms for one reason. They have a tapered chamber which makes it somewhat self ejecting. AR's are pretty much straight walled chambers which adds to the problem.
BTW-my CMMG gas port is .079.
If you got to shoot steal case try silver bear. It think it is pretty good stuff and have never had any issues with them.
Don't shoot Tula, or pre-WPA wolf. If it works with Barnaul or the bears, or brass, the rifle is fine, it's the ammo that's falling short.
Some rifles are able to run the underpowered Tula/Wolf. If yours won't, get over it, it's $10/1000 difference.
Have you tried tightening the gas key? A lot of the time FTF or FTE is caused by a loose gas key leaking pressure.
The shorter the gas system the more sensitive they are to different loads. Mine only works with 55 grain or heavier bullets and higher pressure loads. Light charge or light bullets do not function reliably.
follwo bp's info. any sbr'd upper i have i always polished the chamber and all of them 7.5 10.5 and 14" all run steel cased ammo w/out any issues YMMV
Steel in general's not the issue - just Tula/Wolf.Quote:
Originally Posted by jim
Most of my rifles choke on old Wolf, but have run fine for over a decade on a diet of Barnaul or the Bears.
i should mention so we can eliminate the tula that the same thing was happening with brass and we had another pistol there that had the same issues as mine...... all the carbines functioned perfectly with all the ammo/mags there
i think were going to try to add an extractor oring to start and keep working with this thing untill it chugs along with tula or i sell the upper and do a 10" :)
Get the heavier extractor spring too!
I doubt throwing parts at the problem will fix it plus why throw out the baby with the bathwater?Quote:
Originally Posted by cofi
Start with the simple things. The gas block idea is a good one-check the entire gas system for any leaks-check that the gas port lines up with the port in the gas block, if the port is blocked partially you've a problem. Gas key tight?
If you get up to Denver slide by and let's have a look.
I would still be rattling DPMS' cage.
what am i looking for leak wise....should i see carbon? ill call dpms but there cust service is the pits and they dont warranty steel cased :(
My experience with Kitty-Kats is that they run fine out of the box, and have a properly sized gas port.
I have mine on an RLL-equipped stock DPMS lower, with a telestock and standard carbine buffer, and it runs through mag after mag after mag of brown bear on full auto with no issues at all. Brown bear is notably hotter than many commercial brass loadings, and definitely hotter than tula/old wolf.
If it FTXs with many different types of ammo, then it's likely a chamber issue. Clean the crap out of the chamber and polish it with a .410 shotgun mop coated in flitz, on a cleaning rod chucked into an electric drill.
If you wish to upgrade your extractor, get the black insert, and extra power wolff spring. You can also stick a #60 viton o-ring (viton for higher heat resistance, as regular o-rings will melt in an AR bolt at operating temps) around the extractor insert for even more stiffness.
Different buffer weights are generally used to fix timing, bounce and recoil issues, not FTX.
Checking for gas leaks usually means checking the bolt holding it in place and making sure its properly staked too.
Quote:
Originally Posted by cofi
well it worked the oring completely solved the issues been through almost 1000 rounds of tula with no fte at all
thanks to rockymtnrifleman for figuring this out :)
Thanks for sharing the fix COFI. I still think however it is treating the symptom as opposed to curing the cold.
Still betting it is over/under gassed.
Quote:
Originally Posted by BPTactical
i 100% agree bp next time im up your way ill be stopping by to have you guys go over the ar .....for now im just happy i can shoot the thing reliably although im fast at clearing jams now :P