New HK-91 jammed

[Wilbur]

I took my "new" HK-91 out and it jammed on the 6th round. The
case was ejected ok, but when I pulled the trigger again I got
nothing - misfire or the pin didn't hit. It's jammed pretty tight too.
I've stripped it down and tried pushing on the charging handle (I
guess that's what you call it) as hard as I dared. What has
happened and how can I get this unjammed? I was shooting
Remington ammo, .308. The magazine well is marked .308, not
7.62, so I assume that is the correct ammo for it. There was no
sign of trouble before this. It was slinging cases about 20-30 feet
with great big dints in them, just like I heard they were supposed
to. I was shooting from a full, original, metal magazine.

BTW, the first five were a nice tight group but low. After adjusting
the sights the last round just skimmed the bullseye. This is with
iron sights.

[Herr Walther]

Is this a true H&K 91 or one of the many clones?

I have never heard of this occuring in an H&K produced G3/91. First time for everything though.

I can think of a few things if this is a clone. If it's real, I don't have a clue.

[Wilbur]

It's a real one. I bought it at a pawn shop that sold it to me on
consignment. It's a pretty big place and they have a gunsmith
there so I took it back to them to check it out. They got it apart
pretty easily. I pushed the charging handle pretty hard, but not
while it was apart. Apparently that was the secret. The problem
was a bent round in the chamber. The top of the round was bent
at about a 5-10 degree angle. The gun is absolutely filthy and
I only fired 6 rounds through it. I cleaned it before shooting so it
got this dirty with the ammo that I bought - Remington. They said
that Remington ammo has been sliding downhill for a while and
that it tends to be pretty dirty. I actually passed on buying some
Remington .22 yesterday because I've had so much trouble with
it, but I did not think it was an indication of their centerfire
cartridges. I'll clean it up tonight and take it back out this
weekend with some Winchester I just bought.

Has anyone had a lot of trouble with Remington ammo? I've never
seen a cartridge bend before.

[johnwill]

I've seen rounds get pretty mangled in a jam, lots of bad things can happen to them. Remington UMC isn't my favorite ammo, but I think you should be able to shoot more than 6 rounds before any gun gets so dirty that it'll jam!

[Wilbur]

You'd think so. I'm not convinced it was because it was so dirty.
It could have been something with the ammo, or possibly with
the gun. It sure was filthy though - it looked like 2-300 rounds
of reload had been fired through it, and the shells were covered
with black soot. I'll shoot some Winchester this weekend and see
how dirty it is then.

[Herr Walther]

If it was that dirty, make sure the chamber and the flutes are clean.
You could have extraction problems if there is a lot of build-up in there.

The chamber and flutes should be relatively clean for reliable operation. Those flutes are the secret to reliable extraction.

[G3]

The H&K G3s, 91s, and any roller lock design rifle will be completely filthy after about 20-50 rds. That's because of the gases passing through the fluted chamber to float the case so the rim of the case is not torn off during extraction. The cases will be very dirty, dented, and scored by the fluted chamber. This is actually a positive feature in combat. You don't want a nice pile of shiny brass piling up next to your position. The dirtiness of the rifle should not have any effect on the rifle's performance. Mine goes easily a 1,000 rds before cleaning, and its a sooty mess . Despite this, not one jam in 4,000 rds. Also, the charging handle is known as the cocking lever. It does not recipiprocate. It really only functions to cock the gun for firing. Also, never take apart the rifle with the cocking lever locked back.

I have a hard time believing that even a bad round would jam the rifle. The misfire probably resulted from riding the bolt forward. The rifle won't fire out of battery. Did the primer have a slight dent on it? Also, may I ask what markings are on the rifle? There are clones out there with HK91 stamped on them and pawn shops are not known for the firearms knowledge or honesty.

The only ammo I know of that a G3 will not eat is CAVIM. The previous owner may have been shooting this ammo and clogged the flutes up with the tar CAVIM uses as a sealant. This may cause the case to get stuck. It only takes about 20 rounds of CAVIM to cause a problem. If the flutes are clogged with this stuff it's going to be a bitch to clean out. Use some kerosene to break the tar down. Although Remington UMC is not the greatest, it should work just fine in a G3. The only rifle more reliable than a real G3 is an AK/ Galil/ R4.

I suggest zeroing the rifle to hit about an 1" high at 25 yrds and leave it alone. Using this zero you will be good to about 240 yards.

If you have any other question feel free to ask.

[Wilbur]

If it's a clone then it's an outright forgery, and a pretty nicely done one at that. On one side it has "HK 91", the serial number "A 055XXX", "Cal .308" and a couple of symbols underneath this with "IC" in between them. On the other side it has "Made in Germany", "HK Inc." and what I guess is an import mark "Arl. Va 22 201". The finish is very good and all the welds I see are very nicely done. It has an adjustable, removable muzzle brake, which I assume is either a dead giveaway or illegal. I don't recall any markings on any of the internal parts when I had it apart, but I'll look again today when I clean it some more.

You can definitely see the fluting marks on the cases, and they are badly dented and the rims look like they couldn't have taken much more abuse before being torn apart. I don't know if the bent round had a dent in the primer or not - I didn't think to look when they showed it to me and didn't think to ask for it either. With the round bent as badly as it was I don't see how it could have possibly gone into battery. My question is how did the round get so bent? The magazine is steel and the only markings I see are "7.62x51" and "IB" underneath that. The ammo actually hits the lip of this thing pretty solidly when it is being extracted, at least outside of the gun. I don't see how a round could be extracted without scratching the hell out of the jacket.

I don't know what ammo the previous owner used, but the pawn shop folks were shooting the white box Winchester, which is what I have now, and said they got 100 rounds through it without a problem. Until I see further proof I'm assuming these guys are honest and they seem fairly knowledgable. They have more new guns than most dealers around here and are the only HK dealer in the area. The Uzi they sold me back in February was genuine and has functioned flawlessly.

What do you mean by "charging the bolt forward"?

[Herr Walther]

Your H&K was built in '82, the mag in '81. It's real enough

[G3]

If your rifle has those markings stamped into the receiver, it is the real deal. Without examining the round its hard to solve the problem but, the rifle should eat about anything. "Riding the bolt forward" means that you ease the bolt forward into battery instead of allowing it to slam forward by spring pressure alone. Riding the bolt forward will often keep the bolt from fully going into battery, especially if the rifle is dirty. If the bolt is not all the way forward, then you will get a misfire. The primer will show a light indentation from the firing pin, but the round will not detonate (hopefully).

I have had very good performance with Portuguese, DAG, Federal, Win USA, Hirtengerger, and even Norinco ammo.

[Wilbur]

In that case I definitely did not ride the bolt forward. I loaded all 20 rounds in the magazine, then fired five rounds, checked the target, fired one more and then it misfired (or missed the primer, whatever) and was jammed. Incidently, I like the sights on this thing - the last round edged the bullseye and was well inside the center square of a sighting target. As long as it doesn't jam again and shoots as consistently as it did before it jammed I think I will be very happy with this thing.

[4V50 Gary]

The HK delayed blowback design is ammo sensitive and the cartridge brass must be a certain hardness for the gun to work. Too soft and it'll be torn apart by the violent extraction of the gun. However, it must be soft enough to expand into the "flutes" so as to allow gas to blowback onto the bolt. Stick with Nato milspec ammo for the HK.

[Wilbur]

The white box of Winchester I have says "Military .308" so I assume that means mil spec?

The gun has .308 on the magazine well. I know that there is technically a difference between .308 and 7.62x51, at least in the specs if not in actual production. Is this gun chambered for .308 or 7.62x51 NATO? Did the Germans just think those dumb Americans wouldn't know what it was unless they put .308?

[4V50 Gary]

Going back to the operation of the gun, it could be that the ammo isn't generating enough power for the gun to operation properly. This would make for a sluggish retraction and half hearted feeding - jamming being the end result. Of course, it could also be that the ammo is too powerful and causes the gun to hyperfunction - that is, feeds too fast for the magazine to work reliably in conjuction with the action. Try to get your hands on some surplus German ammo and see if that works.

By the way, I've used Cavim but I haven't shot more than three boxes of it at a time. I won't press my luck to see if it'll take the fourth box (and besides, my gun is living in Nevada now ).

[Wilbur]

I guess ammo was the problem. I shot a box of Winchester white box through it with no problem. It didn't damage the cases nearly as badly as it did the Remington. It shot nice tight groups too, even with iron sights. I'll order some surplus ammo for it and see how it shoots that. I was planning on ordering some more magazines for it from AIM. How well does the .308 Hirtenberger shoot? Anybody get any duds with it?

[James K]

I know guns are marked 7.62x51 or .308 Winchester, but in fact the commercial ammo is loaded to a higher mean pressure than military spec and the brass may be softer. I would try the rifle with US GI ammo or any of the good 7.62 NATO military ammo around (Portuguese, Radway Green, etc.). The Hirtenberger should be OK, but much more expensive. That rifle is very susceptible to differences in ammo pressure from what it was designed to use.

Also, if the round is bent, the magazine should be suspect.

The Arlington address is probably that of H&K USA, which is in Arlington, VA.

Jim

[dZ]

a buddy has a 91
at the range it hurls the cases 3 benches over and those babys are embossed, dirty, and quite hot

the brass from an 91 is quite recognizeable

especially if it lands in yer shirt

[Wilbur]

I knew this thing was going to throw brass, but it is amazing to watch. It was throwing them 30-40 feet, and one of the cases went at least 50. Afterwards, shooting the Mauser was pretty pleasent - the ejected brass just drop to your feet.