So how does one adjust the bolt gap if and when you need to? It is a set the barrel farther back in the trunion type of operation, or... ?
J&G Guns is about an hour and a half ride from me and I've been doing business with them for about 10 years so they cut me some slack. Those of you who had me hand pick good yugo kits and have them shipped to you remember this. I looked at a total of 18 different C93s, all new in the box. I also did extensive research on the prduct prior to looking. My first one that I accepted was a low serial# one with a Special Weapons receiver (70X). This is the same receiver Vector uses for their builds and is most like the true HK93 receiver. I took it home and it refused to cycle. In fact, all three rifles I ended up taking home refused to cycle(more on that later). When I inspected the internals of the rifle the bolt gap was .006 and the rollers were somewhat worn as was the tapered locking pin that forces the rollers into the trunnion when in battery. Now that I know what I know, I should have kept this rifle, as the repair would have been easy with a new set of oversize rollers and a new locking pin. The receiver on this one was excellent with all dimensions in spec and very clean welds. Nicely parked and the barrel was located in the proper spot. With oversize rollers and locking pin this rifle would have bolt gapped at about .014 to .016 and would have given years of good service. But I returned it and proceeded to look at another 5 new rifles.
They were all high serial# ones in the 7000 range and used what I now know were Hesse receivers. The Hesse receivers are actually G3 receivers modified to fit the 93 and many after market parts will not readily fit. Mags tend to be loose in fit and the welds tend to be less than great. The biggest problem I noticed was that on three of the 5, there was no discernable bolt gap so I rejected them out of hand. I did check the bolt and rollers on each and the rollers were not worn out at all. This made me conclude that the barrel was installed improperly in the trunnion. This can be fixed with a reinstall of the barrel and an oversize barrel pin. Forth one I looked at had a good bolt gap of .012. I took it home and it too failed to cycle. I cleaned each rifle prior to shooting. I went through about 30 rounds hand cycling and it started to shoot. By the time I put a 40 rd mag through it it was operating flawlessly. Bolt gap had shrunk to .007 after the session.
I Kept the second rifle and went back to JG and asked the salesman to only pull boxes with serial#s below 2000. I brought my feelers with me. Found one with a bolt gap of .017 and serial# 15XX, built on a Special Weapons receiver. Took it home and it also failed to cycle the first ten rounds but after that it ran sporadicly with FTE being the biggest problem. I noticed the rollers were not moving smoothly in the bolt and tended to bind. I took the entire matching bolt assembly out of the other rifle with the high serial# and swapped it for the bolt assy. in the low serial#. It shot perfect and 300 rounds later, not a falure of any kind. I finally had a good one. I returned the other one. My conclusion on the falure to cycle is that the fluted chamber has a bunch of crud buildup in the flutes. Even if you clean the rifle first, unless you have a special brush to clean out the flutes the first 10-20 rounds are needed to blow out the crud from the flutes and get it operating properly.
Some observations and conclusions.
1. When I changed bolt assemblies in the two rifles, the bolt gap remained the same for both rifles. IE: the bolt gap remained .007 in the high serial# one no matter which bolt assembly was installed. Conversely, the bolt gap remained .017 in the low serial# one regardless of bolt assembly. This tells me that barrel installation is the biggest overriding factor in these rebuilds.
2. Century is just taking the returns and sending them back out the door without any repair. The low serial# one had a faulty bolt assembly otherwise it was great, changing the entire bolt assy. brought the whole rifle into HK spec.
3. From research, I've concluded that Century is just grinding off the rear of the bolt to create an illusion of true bolt gap on many of their returns. Century is not reseating the barrel to correct relation to the trunnion for proper bolt gap. The key here is that the life of the rifle is directly proportunate to the size of the bolt gap. The larger the gap the longer the rifle life. Small bolt gap can be extended with larger rollers and new locking pin. If you buy, make sure you have a bolt gap of at least .010. With a bolt gap of .010, check for worn rollers and locking pin. If they are worn, THIS IS GOOD, you can cheaply replace both and you'll have a good gun. If the rollers are not worn, then the barrel is not set properly and you have a much more expensive proposition in getting it to operate correctly.
4. The rifles with the low serial#s are worth more at resale than the rest. The buyers of any HK clone will ask, "What's the bolt gap?" Immediately followed by, "Who made the receiver?" The SW receivers with spec. bolt gaps are worth approx. 250.00 more than the others with Hesse. The dealers arn't hip to this yet and there are good low numbered ones out there.
5. The furniture and lower trigger housing is pure Century crap and looks/feels it in every way. The furniture has been epoxy painted over and the lower shell is very plain and flimsy. HK parts are very, very expensive compared to AK stuff but you can shop and get a deal if you're willing to compromise.
The Clipped and pinned lower shell I got from Shockwave technologies is gov. contract full auto housing from Malaysia. It is 49.95 Vs. 99.95 from any other vendor. I would have preferred black furniture but it is very expensive for the 93. 200.00 for the new HK stock and 135.00 for the new forend. I went with green and used an MP5 stock 48.00 new HK factory and a G3K forend from Numrich for 55.05. The bipod is POF (Pakistani Ordanance Factory) and made under HK contract. 75.00 vs. 200.00 for a german made one. Mags........well there's the rub. The 40rd. alum. ones are about 30.00 and work great but the bipod is useless with them. The 30rd steel ones are 59.00 on strumgehwer but are genuine HK German made new. The rifle is very handy with these.
All in all it is currently my favorite shooter and a roller locking bolt system is a joy to shoot when you have a good one. Still if the SHTF, my go to would be one of my AKs. The HK draws a crowd at the range and is barrels of fun but the AK is a much more stable, dependable platform.
Sorry for the extremely long post, but I wanted to share all the info I had on these rifles with you guys. What to look for, what to watch out for.