HK91 Locking Piece for Sound Suppression

In order to use a can on a PTR-91 or other G3/91 clone, apparently it's necessary to use a different locking piece that slows down the bolt carrier with the increased back-pressure.  Rim Country Manufacturing sells a #17, 36° part that fits the bill.  $50 ain't so bad.  They also have US-made trunions, bolt carriers, and bolt heads for MP5- and 53-type actions.

HK-91 Miscellany

Numrich's website can be difficult to navigate, so here are the HK-91 and HK-93 pages.  I want to get the G3 schematic poster!


Also of interest is the Command Arms AR-15 stock adapter for 91-pattern rifles, available at Apex.  I didn't see it on their webpage, so I presume they discontinued it, like Smith Enterprise discontinued the Vortex for the 91.  TAPCO makes a plastic one, but I want metal.  ACE apparently makes an aluminum adapter, but I've read that it can't be used with the standard buffer, whereas the CAA one uses the standard recoil spring assembly.

PTR Commentary

My remarks on a link to an article posted by SayUncle:

I like mine: from sandbags I was getting 3" at 200yds (1.5 MOA) with old Australian surplus using a Hensoldt 4x scope (with temps in the 30s, so I was probably getting a cold-bore shot every string...). The recoil is heavier than an AR-15, but you get used to it. Especially if you put the wide handguard and Magpul PRS stock on there, which makes it really heavy!

Downsides to the HK91-style rifle are two: it beats the hell out of brass, and it doesn't have a last round hold open. The former is only an issue if you reload (which is why I only feed mine surplus). The latter is a serious demerit, IMO, as I'm not going to stick tracers in for my last couple rounds. Still, as Boston T. Party opines in his "Gun Bible", it'll pretty much always work, which is what you want in an SHTF rifle.

CDNN has the best price on the gun. RTG has good prices on surplus accessories; buy new at HKParts if you're rich ;-)

I still despise CTD, though....

HK Builds 2

Looks like HKParts is selling a flat bending jig for HK-pattern rifles.  It'd be pretty neat to put an HK91 clone together, but I'd have to learn how to TIG/MIG weld first.  A hydraulic press is necessary for affixing the trunnion to the barrel, and for some jigs, forming the flat.  So one needs either a well-equipped shop, a friend with said shop, or a build party in the vicinity.

I also came across a pictorial guide to bending a flat and building a CETME.  Way cool.

The jig shown in a link on my earlier build post was cooler than either of the above, though.

HK. Because you suck. And we hate you.

Larry Correia is a funny guy.  Mention of the HK rant has crossed my screen before, but I'd never read the whole thing.  It's hilarious!  I say that as a guy who likes his HK91 clone.  I'd dearly love to get an MP5 submachinegun or even a G3, but I'm a civilian and I'm too poor.  I'd even like to get a real semi-auto 91, but for 3 grand, it's probably more practical to get an M1A and some training.  I'm also pissed off about their piston AR-15 that doesn't take standard lowers.  Ah, HK does have an Apple-like aura about them, except they're not as ergonomic.

As an aside, you can tell a real HK fanboy from a poseur because the former knows how to pronounce 'Koch' in English (it's 'Coke', as is Koch Industries).  I'm kind of a fanboy, but I'm also a realist.

HK Builds

Since I'm getting more interested in gunsmithing and was in a superfluous meeting, I went on HKPro looking for interesting stuff and, in particular, build info.

G3 DMR kit from Bravo 5
Sexy jig for bending receiver flats
...a few more build links on Calguns
HKParts' contract barrels are POF, huh?  Shit...

Henshold-Wetzlar

The Hensoldt-Wetzlar scope for the G3 is nice, but the lens covers are annoying to open.  I've been looking for a replacement, but it seems like the Butler Creek ones aren't quite the right size for the bells.  A discussion on HKPro claims that the #3 covers should work.  Midway's chart, however, says #3 is 35.3mm, whereas I measured 32mm using a ruler.  I'm going to have to break out the calipers.  In further searching, I found a site that details the 3 generations of H-W scopes.  I have the 3rd gen scope, it seems.

Plastic Port Buffer

Just found a non-marring port buffer for the HK-91. I've heard that the metal ones scratch the receiver when removed, which is undesirable. Might have to get one of these to try out.

HK Cleaning Gear

The chamber face area of HK-91 style rifles is a bear to clean. There's a factory chamber face brush available, but it has stainless steel brushes, so I'm a bit leery. HKParts sells the factory brush for $25.

There's also a U.S. manufacturer, E&L Manufacturing, of a similar brush. The clone chamber face brush plus the receiver cleaning brush and rod cost the same as the factory brush itself. Hard to tell what the relative quality is without having both, however. E&L has a brass catcher for the HK-91, although it's unclear whether that will function with a port buffer and claw mount.

HK Trigger Packs

I didn't link this earlier, but a post on HKPro indicates that HK is now putting serial numbers on trigger packs, bolt heads, and bolt carriers, and aren't accepting orders from anyone except law enforcement. This apparently is due to a new German law on firearm parts for export, and is not just an HK thing.

This really sucks in that real HK parts will go up in price. On the other hand, I'm sure someone in the U.S. market will step up to the plate and make clones. I've seen U.S.-made bolt carriers and bolt heads for the MP5, anyway.

MP5s

More interesting links to HK clone sources. (Refer also to my previous G3/91 links.)

HKPro had a post that tipped me off to a MP5 flat manufacturer, LSC. They had a link to Rim County Manufacturing, who sell a U.S.-made PSG-1 barrel. For only $725! (Ouch.) It's 1:11 twist, target crown, 25.5 inches.

Might have to look into an MP5 clone build with a flat from HKParts (previous post on building an MP5).

Tiptacon

A while ago I found a site with a guy offering to add a rail to an HK-91 wide handguard for mounting a vertical foregrip. For some reason I didn't post it here. The real interesting thing, though, was the technique of using a sling with the foregrip to minimize the effect of recoil. Apparently, with an appropriate sling tension, by pushing forward on the foregrip, one can better keep the rifle in line with the target. It certainly made me revisit my stance on foregrips.

HK G3/91 Resources

Lately I've been consumed with the Heckler & Koch G3/91, and have read up extensively on it. Here are some of the fruits of my labor:

Parts Stores:

• Numrich - the best for general parts
• RTG - the cheapest source for mags, surplus parts, and some new parts
• HKParts - expensive, has the MagPul stock, rear sight adjustment tool, and MSG-90 buffer
• HKSpecialist - expensive, has the vented handguard, bipod, PSG-1 parts
• PTR - manufactures HK-91 clones on HK tooling from Portugal, and they also sell some parts
• HKPartsOnline (not very useful)
• Arizona Response Systems - HK refinishing and parts (no pictures)
• Hi-Vel (parts list, no pictures)
• POF-USA - manufactures some parts on HK tooling, like PTR, but their website is slightly broken
• Copes Distributing - has a good price on the Hensoldt scope with mount

Build Information:

• HK-91 disassembly/reassembly
• G3 build using Century Arms receiver
• G3 trigger disassembly

Mod Information:

• Williams' custom set trigger
• 'Smiths for G3 clones
• C&P for SEF grip frames
• Rail mod for the HK wide handguard

Specific Part Info:

• BufferTech's plastic buffer
• Picture of the famed heavy bipod (which I can't find for sale anywhere)
• Here's a good price on HK's mag loader/unloader
• Knight's Armament makes a RAS for the HK-91 (see the bottom of the link), sold here
• Brugger & Thomet Tri-Rail Handguard - The picture shows a brass catcher on a G3, but all DSArms has is one for the MP5
• Smith Enterprise makes a version of their Vortex flash hider for the HK-91 (spec), sold only by Brownell's
• Compensator
• "Recoil Eliminator", aka "tank brake/comp"
• PSG-1 style Ergo Grip for metal grip frames

List of Surplus Ammo

As for forums, HKPro is pretty cool. Useful posts:

• How to check the bolt gap
• Installing a heavy 2-stage buffer
• Picture of the different buffer options (G3, MSG-90, G3 heavy, HK-21)
• How to bend an HK flat
• How to avoid marks from attaching a claw mount (more info also on mg-42.net)

Manuals and such:

• G3 Armorer's Manual (found here)
• G3 Green Book

I may update this post as I find new stuff. Last update: 2008.04.13 20:25.