http://www.65grendel.com/forum/album.php?albumid=59Just put this together took it to the range first shot with scope dead nuts at a hundred yards, went to fire second round nothing then noticed chamber open with round stuck at an upward angle slightly sideways. Wolf MPT ammo.Cleared the jam the next round the same thing.Using ASC mags from Rainier, changed two more mags same thing.At one point I was able to get off 6 rounds but jammed again.When I remove the rounds the bullet and casing are bent sideways to crap.
16" Sabre Defence M4 chrome lined barrel carbine length
Rainier Arms Billet upper M4
Quentin Defense billet lower
Spikes Tactical trigger kit
Y/M Auto Carrier with Sabre Defence bolt
http://s882.photobucket.com/albums/ac21/...4/Grendel/
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Got pics of inside the rifle & damaged ammo? Is the nose of the round jamming into the top of the barrel extension?
Had the samething happen this weekend on my Satern barrel/bolt. I found this feed and am certain this is what is happening to me.
http://www.65grendel.com/forum/showthrea...il-to-Feed
txgunner00 Wrote:Got pics of inside the rifle & damaged ammo? Is the nose of the round jamming into the top of the barrel extension? Trying to upload photos but for the life of me I can not, I have never had this issue.
Nose of round looks ok sides a little scratched.
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I don't see anything out of place in the barrel extension or feed ramps.
Start with the ejector pin as that seems to have been a problem more than once. It looks like something is impeding the rounds from popping up in line with the chamber and the bolt is over riding the cartridge. Could be magazine (feed lip) related but you said all 3 did the same.
txgunner00 Wrote:I don't see anything out of place in the barrel extension or feed ramps.
Start with the ejector pin as that seems to have been a problem more than once. It looks like something is impeding the rounds from popping up in line with the chamber and the bolt is over riding the cartridge. Could be magazine (feed lip) related but you said all 3 did the same.
All of my mags are ASC 25 round, like I said I did get off 6 rounds with one of the mags, but all the cases have a scratch some deeper then others.I did order another bolt today from AA, the other one I have is a Sabre which came with the barrel,and I was going to buy a extra bolt anyway.But I will check the ejector today, and hopefully can get out this weekend and give it another shot.
Thanks all for the help will keep you posted.
Look at the mags from the side and compare them. Mark each mag with a number so you know one from the other. Sometimes one feed lip will be correct, and the other will be at the wrong angle. The mag will feed fine from one side, and then encounter the exact type of malf you described. I'm not sure about the ASC mags, but I've seen it with CpRoducts mags. Since ASC acquired CProducts tooling, it's plausible that they could repeat the same QC errors. I looked at all your photobucket photos, and your feed ramps look pretty nice actually.
If you can take pics of the mags from the sides, showing the feed lip angles, that will help.
Also, the meplats look fairly large on the Wolf MPT's, and that increases the likelihood of the bullet tip hitting the edge of the chamber, causing a FTF malf. Try some Hornady 123gr Factory AMAX and see if there is any difference. Load 2 rounds in each of your mags first, to check both feed lips, and see if the bolt locks back as well. Then load more. I know the Hornady isn't cheap, but the projectiles are pointed with the polymer tips.
In your PB pics, I also saw some PPU brass with what looks like a blown primer. Is that correct? If so, don't shoot that ammo anymore.
Will take some photos of the mags tonight.As far as the primers go I had about 5 blown out like that, and a few rounds where they were tilted.
I just picked up the ammo it was Wolf MPT from Wideners.I do not know if they are carrying old stock or what, but I went through this last year with 32naa ammo where the rounds were jamming only to find that the cases were oversized.I had to take the gun apart and hand fit all the rounds with about a 30% fallout rate, and then had no issues with the gun.Sent the bad stuff back to Corbon and they sent me a couple of boxes.
Looked at the ejector last night and the pin itself looks a little de-formed mushroomed,should the ejector be at bolt height?
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05-15-2012, 10:46 PM
(This post was last modified: 05-15-2012, 11:10 PM by txgunner00.)
Here's some pics of my bolt and mags. Can't tell much difference.
[ATTACH=CONFIG]1403[/ATTACH][ATTACH=CONFIG]1404[/ATTACH][ATTACH=CONFIG]1405[/ATTACH]
Your problems could be caused by a gas issue. If you are under gassed it's possible for the bolt to only half way grab the next round and jamb it into the bottom of the barrel extension. Severely over gassed AR's can also produce similar malfunctions. Which way was your brass ejecting. Perpendicular to the rifle, forward or behind?
The blown primers are concerning. I don't believe the MPT loads are known for being hot but I've never shot them myself.
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05-16-2012, 01:27 AM
(This post was last modified: 05-16-2012, 01:29 AM by Variable.)
txgunner00 Wrote:The blown primers are concerning. I don't believe the MPT loads are known for being hot but I've never shot them myself. I used to shoot a butt load of the MPT ammo and blown primers were never a problem for myself nor do I recall anyone else having that issue.
I was able to induce it by superheating the ammo during a redneck temp test though. Placing an MPT loaded mag on my truck's dash for hours at the range during high summer put the temp well over 160 degrees. I had to jerk my Kestrel off the dash because I was afraid I'd kill it too.LOL The mag burned my hand so I had to handle it with a t-shirt. I trotted forward to the line and shot a ten round string over a chrono real quick before it had time to cool down. Two of the primers popped and the pressure was really high, but no other problems.
![[Image: HighTempWolf-pop.jpg]](http://i307.photobucket.com/albums/nn291/Variable556/HighTempWolf-pop.jpg)
As Bill A. said: This was beyond the design parameters for the ammo. 
Perpendicular to the rifle.The gas block is a vltor low profile, and I have a dimple jig for it so the location is dead on, I have used it for other builds, but on the chance I screwed up I will test it out, but I believe I would be on the over gassed side if anything.
I had quite a few of the primers blow out, never seen anything like it, again this is my first grendel.I could slow it down with a H or H2 buffer, I am currently using a standard buffer.
Also someone suggested trying out the Hornady A-Max, which I will try out this weekend.I think the first thing though is to verify the gas block and go on from there.
I have about 10 boxes of the Wolf MPT, at this point i think I will get rid of it.
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You should probably be running an "H" or "H2" buffer with a carbine gas length on a 16" barrel. That said, there is definitely something going on in your system. You shouldn't be losing primers in your MPT ammo.
I need to see side-view pics of your mags in order to see of the feed lips are out of alignment...as if it were inserted in a weapon and you took a side view shot of the gun, but not inserted of course.
Who made your barrel? Ah Sabre. It could be a case of too tight of a bore after the chrome-lining process, that is my best guess at this point. Mic your grooves and lands at the muzzle and see what you get. A tight bore will do what you see on those PPU cases.
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The deformations on the case head most likely are caused by too much pressure too early. It also could allow the primers to pop. As Variable said, try a heavier buffer. Hopefully that fixes it and it's not something like a tight bore with Saber being closed up.
txgunner00 Wrote:The deformations on the case head most likely are caused by too much pressure too early. It also could allow the primers to pop. As Variable said, try a heavier buffer. Hopefully that fixes it and it's not something like a tight bore with Saber being closed up. What I did do last night is again check the gas by blowing through it and it is definitely clear.Took apart the carrier cleaned the bolt and inspected the gas rings all were off set so no issue there, oiled up and put back together.Cleaned the chamber and barrel really well, and picked up three boxes of A-max ammo last night, and added a H buffer, with a H2 on standby when I go to the range on Saturday.
Funny part is I also assembled a 5.56 using a Sabre 1x7 chrome lined 16" midlength barrel,and that one has a failure to extract the case, and is not loading another round, it's a great single shot gun but thats not what I want.Checked that one out last night and it also seems to be in order, but I believe the chamber just needed a good brushing, and I also need to slow the cycle time down a bit.
This is kind of funny because the more I spend on a barrel the bigger problems I have run in to, the AR;s I have with medium range price non chrome line barrels did not miss a beat from the first time I pulled the trigger.
I have learned where to source my barrels, and I have yet to have any issues with the 4150 CMV Chrome-lined pipes from BCM for the 5.56 guns.
I also have had great results (100% function so-far) with AR Performance 5.56 barrels on several guns. These are nitro-carburized barrels with insane Rockwell surface hardness. I used one for my BIL's 16" Carbine, one for one of my 16" Carbines, and I have 2 more-one that I tested already, and they eat ammo like it's fun. The chambers are so hard and smooth, that even steel cased is supposed to run through them like crap through a goose.
That said, a rough chrome-lined chamber is not what is going to produce over-pressure issues. A tight bore will. Have you mic's your groove and land inner diameters yet at the muzzle?
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