Failure to Feed

[Blusqualo]

Greetings from chesaning, mi,

I have a 450 that won't pickup a round after firing, it otherwise functions fine.

I assembled it myself from mil spec components from various manufacturers, except for some of the upper receiver. I had a custom barrel made by Jim from Apache Gunworks in LA, and had him assemble the muzzle brake, gas block and tube, and barrel to the upper.

The muzzle brake was a custom 2" with 15 degree to rear porting on a round brake that doesn't have sides or need to be indexed.
The barrel was a custom 21" stainless heavy barrel with 1:16 twist and a rifle length gas system. With an adjustable gas block and a free floating handguard. The lower has an M4/6 position butt stock

It shoots phenomenal with its 6.5-20 x 50 Leupold scope, last fall I went 3 for 3; a 6 pt at 235 yds on opening day, and does at 205 and 215 yds. (I use a leupold rangefinder to range and confirm) all one shot kills where they either didn't take a step or made it 5 and 15 yds.

At duncan's gun shops 200 yard indoor range I shot a three leaf clover with a 4th shot touching one of the "leaves", so a touch less than 1 MOA at 200 yds, which is less than 1/2 MOA at 100.

So needless to say the barrel/upper are incredibly accurate and shoot a little flatter than expected with factory Hornady ammo, and most handloads with 200-250 gr bullets, I just need to get it to cycle reliably.

I have tried numerous mags and modifications to them, different buffers and springs, i have tried various handloads from mild to max, and even different lowers. With a friends Wyndham lower it cycled sporadically, but not reliably.

I wanted to get a gurus 2 cents on how to proceed. I have read some that leads me to think the rifle length gas tube could be a likely culprit.

Troy Lapine
Blusqualo1@aol.com


M Go Blue

[plant_one]

we'll need more informatino on the load you're working with to further diagnose things

brass type
primer
powder & charge weight
bullet

buffer and spring

additionally if you have any pics of the failure to feed that may be helpful.

the more info you can give the better.

also

you say you have and adjustable gas block.... is it safe to assume its in the wide open position?

what is your barrel length? what gas port size is in the barrel?

[Blusqualo]

The load I am working with is usually Hornady 250gr FTX factory ammo

I'll have to check on the buffers and springs

The gas block is wide open or pretty close to wide open without the set screw falling out.

The barrel is 21" and the muzzle brake is another 2"

As for a picture; After a round is fired the bolt closes all the way forward without picking up the next round. I have put 350 - 500 rounds through it so far.

Troy

[lungingturtle2]

Tony, I'm not a lot of help but have a few questions. Does the bolt lock back after last shot, with a rifle length gas system it could be short stroking. Also are you running the bolt wet (more than usual light lube) sometimes it takes more than a few cycles to break in a new bolt and receiver. If short stroking is the problem, you may have to open up the barrel gas port slightly, but I'd try all other options first. I'm sure another member with more experience than me will chime in with more ideas. Good luck, sounds like you have a real shooter as far as accuracy goes.

[Blusqualo]

Tonight i will check to see what it does on the last shot as far locking back or not. I don't quite recall off-hand. Yeah, I was pleasantly surprised on the accuracy...while I was for the barrel I waswondering if the 1:16 twist was going to be too fast, after seeing pretty much every other one was 1:24, and a few even slower than that.

I do remember that with some lower powder hand-loads I had some failure to ejects, and a couple stove pipes, regardless of the bullet (185 gr xtp, 200 gr ftx, 225 gr ftx, 250 gr ftx)

[Blusqualo]

One other thing of note, after putting a few rounds through, the underside of my bolt carrier is brass colored.

[bushmeister]

Make sure your gas block is lined up pefect with the barrel port and Loctite the screws in place. If it is partially blocked, it will do exactly what your are describing.

[plant_one]

so you're having this issue with factory ammo as well as handloads? that definatly lends itself to being a mechanical issue with the build and not an ammo issue then. factory 450BM ammo has more than enough stank behind it where it should reliably cycle a otherwise functional firearm.


your BCG by nature is going to rub a little bit as it travels backward over a loaded round in the magazine and pick up some brass coloring on the bottom. thats normal, unless its an excessive amount anyway and you're marring up your brass significantly.

as always pics will be helpful.


with 300+ rounds down the tube, its well broken in, so bolt carrier fitment in the upper shouldn't be the issue, but making sure you're running your bolt well lubed can only help things. i assume that when you hand cycle it, the bolt appears to drop normally and without issue?


are you working with an adjustable stock? or is it an A2 style fixed stock? was your buddy's wyndham lower a different stock configuration? knowing the buffer weight and the spring coil count might be helpful, or it may not. please check those two to help eliminate a possible variable for us.


do some testing with a single round in the mag to confirm that you get BHO (bolt hold open) on a single round every time. If thats the case you likely dont have an under gassing issue.


one thing to note - since you use apache gunworks to assemble the custom barrel, break, gas block/tube and attach that to the upper... he does guarantee all his work (according to his website). i guess i should ask if you've contacted him about your issues as a possible warranty issue? also if you can, see if he'll give you the gas port diameter he put into the barrel as well (if he still has that info available). that will be a useful bit of data to helping diagnose things here.

[plant_one]

Make sure your gas block is lined up pefect with the barrel port and Loctite the screws in place. If it is partially blocked, it will do exactly what your are describing.

^^ this is a valid concern as well, although since it was gunsmith assembled, probably a bit less likely. still worth a check!

[Al in Mi]

be interested to see what size gas port he used. It might need to be opened up to your gas tube size, then throttle it down with your adjustable gas block.