View Full Version : Brand new Sabre Upper "short stroking"...
I BOUGHT A BRAND NEW SABRE DEFENSE 556 NATO 16" FLAT TOP UPPER, INSTALLED IT ON A BRAND NEW DPMS LOWER , TIMNEY 4LBS TRIGGER SYSTEM, BRAND NEW AR15 BUFFER AND BUFFER SPRING.USED BRAND NEW FIOCCHI AMMO 55GR.BRAND NEW MAGPUL MAG SYSTEM.
THE VERY 1ST TIME AFTER BUILDING IT...GUESS WHAT...IT FIRED ONLY THE FIRST ROUND, THE CARRIER WAS NOT ABLE TO LOAD THE NEXT ROUND.OR WHEN IT DID, THE FIRE PIN WAS NOT ABLE TO FULLY STRIKE THE AMMO ,JUST A CLICK SOUND...
THE CARRIER ASSEMBLY WAS NOT EASY TO SLIDE FREELY ON THE UPPER HOUSING..NOW I LUBRICATED ALL THE CARRIER ASSEMBLY AND WILL WAIT UNTIL NEXT TIME AT SHOOTING RANGE...
DO YOU BELIEVE IT'S A PART MALFUNCTION OR JUST LACK OF USE AND LUBRICATION?
I REALLY CAN'T BELIEVE SABRE DEFENCE DIDN' TEST IT BEFORE SHIPPING IT TO MIDWAYUSA...
Quiet-Matt
04-18-10, 16:12
Did the BCG come with the upper? Who made it?
yes the BCG came with it and I belive it must be SABRE too...
ForTehNguyen
04-18-10, 16:48
if you cycle the rifle manually are you able to pull the bolt back with little effort? If you take out the buffer spring, the correct one should be 11" long. Sometimes rifle buffer springs (14") make their way into lowers and it will not work in a carbine tube. Something easy to double check, and one of the first things to start eliminating sections of the gun that could be causing problems.
an AR is easily able to fire without lube, do you have a friend that has another AR15 bolt to swap out and check if anything changes. On a normal AR the bolt carrier should move very easily even without lube.
I have another AR-15 carbine "COLT" ,that's the same buffer and spring I used on my new build to test it...
I will put the colt carrier on it to see what happens...
Is the sabre defense gas port smaller than the other barrels ?
if you cycle the rifle manually are you able to pull the bolt back with little effort? If you take out the buffer spring, the correct one should be 11" long. Sometimes rifle buffer springs (14") make their way into lowers and it will not work in a carbine tube. Something easy to double check, and one of the first things to start eliminating sections of the gun that could be causing problems.
an AR is easily able to fire without lube, do you have a friend that has another AR15 bolt to swap out and check if anything changes. On a normal AR the bolt carrier should move very easily even without lube.
ForTehNguyen
04-18-10, 17:31
gas port or gas block misalignment problems would be the next things to suspect, if the buffer and upper/BCG parts are eliminated.
If the bolt is hard to charge back, it could mean two but not limited to things: rifle spring inside a carbine tube, upper/BCG out of spec.
gas port or gas block misalignment problems would be the next things to suspect, if the buffer and upper/BCG parts are eliminated.
If the bolt is hard to charge back, it could mean two but not limited to things: rifle spring inside a carbine tube, upper/BCG out of spec.
the spring is a carbine spring for sure ,it worked perfectly in my colt carbine.
the buffer too came from the colt for testing it...
so i will just put the Colt BCG on the sabre upper and see what happens...
I will let you know...
Aren't assembled uppers made for easy drop in istallation?
could it be a defective part from SABRE?
BTW ,how high is the quality of sabre defense rifle parts?
ForTehNguyen
04-18-10, 17:56
Saber is suppose to be pretty good up there with Daniel Defense, Colt, BCM, etc. Mistakes can still happen obviously.
does the colt bolt feel any different inside the sabre upper cycling the rifle manually? Try sabre bolt in colt upper also to see if anything is different there. Bolts should move freely back and forth inside the carrier, and the carrier should move freely inside the upper, even without lube. Gotta keep ruling out parts.
Ive encountered a bolt once that got stuck in the carrier when pushed in and it was very hard to pull the bolt out of the carrier. It turned out the bolt carrier was out of spec and had machining marks inside where the bolt goes in, the gas rings got caught up on those machining marks.
I had a similar problem recently with a rifle I built. It wouldn't lock the bolt back after the last round and was short stroking about every 3rd round. I swapped in an "H" buffer from my other rifle I had with me and the problem was completely eliminated.
Is the gas system a carbine or mid length?
Is the gas system a carbine or mid length?
that's exactly what i bought:
Sabre Defence AR-15 M4 Flat Top Carbine Upper Assembly 5.56x45mm NATO 1 in 7" Twist 16" Barrel Chrome Lined Vanadium Alloy Matte with Flip-Up Sights Pre-Ban
Includes:
•16" Chrome Lined Vanadium Alloy Barrel w/M4 Feed Ramps
•Carbine Length Gas System
•5.56x45mm NATO Chamber
•M4-Style Oval Handguards
•A2 Flash Suppressor
•Flip-Up YHM Front & Rear Sights
•Bayonet Lug
•Charging Handle
•Bolt and Carrier Assembly
I would perform a gas ring check and ensure that the gas rings are good. I would also make sure that the bolt carrier key is tightened and properly staked.
Carbine buffer springs should be between 10 1/16 and 11 1/4 inches long.
If everything checks out and it still will not run I would contact Sabre and send it back.
I would perform a gas ring check and ensure that the gas rings are good. I would also make sure that the bolt carrier key is tightened and properly staked.
Carbine buffer springs should be between 10 1/16 and 11 1/4 inches long.
If everything checks out and it still will not run I would contact Sabre and send it back.
Tks iraqgunz ,the gas key is tightened and staked.
the gas ring to tell you the truth,I don't know how to disassemble the carrier to get there...do you have any pdf manual?
tks.
It’s possible that the YHM gas block/front sight is not installed right and not allowing the enough gas to get to the BGC.
Here is a link to the U.S Army’s Operator’s manual. Page 12 through 14 covers the disassembly of the BGC.
http://generalcartridge.net/Documents/united_states_army_tm_9-1005-319-10-c3%20-%201_may_1994.pdf
ForTehNguyen
04-19-10, 11:57
the bolt should cam back and forth easily with slight resistance inside the carrier.
the bolt should cam back and forth easily with slight resistance inside the carrier.
that's exactly what was not going on...there was some kind of difficulty to push the cam back and forth... so I lubricated all the parts with BENELLI MF-82 oil ,and worked manually pushing the the bolt cam back and forth a 100 times...it got easier..let's see tommorow at the range...I am looking forward to it...
tks a lot.
any other advice?
I would perform a gas ring check and ensure that the gas rings are good. I would also make sure that the bolt carrier key is tightened and properly staked.
Carbine buffer springs should be between 10 1/16 and 11 1/4 inches long.
If everything checks out and it still will not run I would contact Sabre and send it back.
What are the length dimensions for a rifle buffer spring?
It’s possible that the YHM gas block/front sight is not installed right and not allowing the enough gas to get to the BGC.
Here is a link to the U.S Army’s Operator’s manual. Page 12 through 14 covers the disassembly of the BGC.
http://generalcartridge.net/Documents/united_states_army_tm_9-1005-319-10-c3%20-%201_may_1994.pdf
tks a lot for the pdf , it's a must for AR owners I believe! tks!
What are the length dimensions for a rifle buffer spring?
they are carbine lenght for sure! colt carbine 16" barrel
ForTehNguyen
04-19-10, 14:24
rifle length springs are 14", but its settled that he has a carbine spring
that's exactly what was not going on...there was some kind of difficulty to push the cam back and forth... so I lubricated all the parts with BENELLI MF-82 oil ,and worked manually pushing the the bolt cam back and forth a 100 times...it got easier..let's see tommorow at the range...I am looking forward to it...
tks a lot.
any other advice?
this isn't normal. Even without lube the bolt should cam back and forth in the carrier with only slight resistance. Remove the firing pin, cam pin, bolt, look or feel into the the carrier where the bolt goes, make sure there's no rough machining on the walls. Rough machining can interfere with the gas rings. I had a similar encounter as previously mentioned with a AR that only fired single shot due to carrier defect. We lubed the bolt, it would work fine for a little while then start malfunctioning again. I guess the gas burned off the lube and it was back to single shot. Replaced the carrier and all was well.
While at the range start swapping out bolts, carriers, uppers to get an idea what parts the problems seem to follow to do additional troubleshooting. But Im starting to suspect the bolt carrier group the most
I'd start by removing the bolt and charging handle. Push the buffer back with a finger and see what kind of resitance you get from the buffer spring. If that's good, start with just putting the handle back in the gun without the bolt, move it back and forth to see what kind of resitance you get if any. And last take out the handle and put the bolt back in the receiver without the charging handle. It should slide back and forth in the receiver, even without lube it should move freely.
Scott
Nobody bothers asking what ammo he is shooting out of this... Interesting
(Nevermind, apparently I don't read so well...)
Nobody bothers asking what ammo he is shooting out of this... Interesting
BRAND NEW FIOCCHI AMMO 55GR
as he listed
yes I went to the range today and dropped a dpms BCG from my 204ruger R15 predator rfile on sabre upper.
It worked every round!
The BCG from sabre btw (YHM) was the problem in my upper.
hope this trhead helps future owners with the same problems.
glockshooter
04-20-10, 13:42
Do you care to actually tell us what the problems was? Was it a problem with the gas rings or something else? Are you also inferring that Sabre used a YHM(Yankee Hill) BCG in your upper?
Matt
Do you care to actually tell us what the problems was? Was it a problem with the gas rings or something else? Are you also inferring that Sabre used a YHM(Yankee Hill) BCG in your upper?
Matt
to be humble as I am, i don't know if it was a gas rings , it seemed to me machinery problems on the bolt.
there was a mark on the gas key screws YHM ,I assume that its yank hill machinery.
tks
spamsammich
04-20-10, 15:15
YHM is who manufactures the screws and is not Yankee Hill, it is a taiwanese or chinese company if I remember correctly. I have seen YHM marked hardware in automotive applications and at trade shows in Taiwan.
ForTehNguyen
04-20-10, 15:19
talk to Sabre for them to get you a replacement BCG.
talk to Sabre for them to get you a replacement BCG.
I emailed them teelling the problem, let's see how it goes...
tks.
One thing is for sure : COLT IS COLT!
yes I went to the range today and dropped a dpms BCG from my 204ruger R15 predator rfile on sabre upper.
It worked every round!
The BCG from sabre btw (YHM) was the problem in my upper.
hope this trhead helps future owners with the same problems.
So have you tried putting the YHM bolt in another upper to see if it still fails?
You should post some pics of the bolt.
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