lrt sass problems

[cchao70@yahoo.com]

Hey so I just got done putting together a lrt sass upper, this is my first rifle i ever built and owned.took it to the range and for some reason the bolt is getting stuck to the barrel. after feeding a round into the chamber and firing it the bolt doesn't move and it takes a lot of force to pull the charging handle back to get the round out. has anyone had this problem before and have a solution? thanks for the help.

[ghitch75]

what ammo?.....did you check the head space?

[TacBlade]

I just shot my new build 5 minutes ago.  It had a similar problem?  I did not check headspace beforehand? I was thinking it was just getting dirty in the chamber, but it should not be that tight.  I believe I will have to check the headspace and verify that this is or is not the problem.  Mine stopped ejecting after about 10 rounds also, the empty case would stay in the chamber and it would try to feed another round in.  I would then pull the mag out and rack the bolt onto the empty case and it was tough to pull it out.  Not sure, but I am going to clean it up and just rack several rounds through it manually with the charging handle and see how hard it is to extract.  If its not to difficult, I would say it is the headspace, I guess?  I am not to familiar with headspacing?  Any thoughts for us here from anyone?  Thanks and I don't mean to hijack your thread!

[cchao70@yahoo.com]

ghitch- the ammo i used was pmc and magtechs and i did check the headspacing.

tacblade- the range employees told me that you need to lube up the bolt carrier really good when its brand new. my problem is that its not ejecting at all. every shot i took the carrier was stuck and i had to use a lot of force to get it unstuck. the bolt carrier doesnt even move after a shot is fired. the carrier gets stuck when a round is in the chamber. the range employees checked it out and said the ammo was fine. im thinking its the barrel but im not sure.

[imschur]

Magtech has a reputation for sticking in the chambers of these guns. Not sure about the PMC. DPMS occasionally lets a rough chamber out of the factory.

These weapons need to run very wet with oil when new. Much more so than an AR-15.

What does the rim of the cartridge look like? Any marks from the extractor? What does the case look like? Anything unusual?

[cchao70@yahoo.com]

imschur- thanks for the info, other than the extractor markings theres no unusual markings on the cartridge. i just recleaned it and oiled it more. and it is extracting better but still getting stuck. i am going to lube it some more and take it to the range tomorrow to test it out. thanks again for the info.

[TacBlade]

I think we are both on the right track!  I cleaned mine up real good and gave it a heavy dose of Lube and It ran 20 rounds without a hicup!

[DocLarsen]

cchao,

The other evening I engaged the bolt in the lugs for the first time with only WD-40 on it and it stuck tight. imschure was online and told me to wrap the butt stock on the floor and it disengaged, but it had me worried for a bit.  I took the bolt and carrier apart and painted every individual part (I think I did the cam pin 2 or 3 times) and the inside of the receiver with Mobil 1 using an artist's paint brush (10W-30 Extended Performance 'cause that is what I use in my cars.) I made sure to do the lugs for the bolt and the lugs and ramps on the barrel extension extra heavy.  And, I'll probably do it a couple of more times before I fire it.  (Now, I am even thinking more seriously about using some Slick 50 or something like that :-)

I have cycled the bolt many times and even cycled several shells through (that I dropped into the chamber since my lower is not together yet) and have had zero problems since.  The Mobil 1 made it slicker than the proverbial minnow's male member!. 

This nothing like firing rounds as far as operation goes, so please keep us informed!  I am putting together an 18" SASS, DPMS chrome bcg and DPMS receivers (A3 upper), so I am very interested.  I just put several more rounds through and checked them with a hand glass.  Only thing I saw was the little bite marks from the extractor and small scratch from where I popped them out of the Pmag they were in, but nothing unusual.

BTW, I don't know if you noticed that someone mentioned the Bushmaster manual being applicable to both Bushmaster and DPMS (I think it was imschur), but it is much better than the DPMS manual, IMHO.

[survivalshop]

Gun Slick or Mil spec grease lightly on the bolt lugs & cam pin , & CLP , run them wet , real wet at first.

Yes , DPMS has quite a few tight/rough chambers.

Note ;WD40 is the last thing you want to use. It will break down other beneficial lubricants. Make sure you get it all out .