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Posted: 3/3/2007 6:33:19 AM EDT
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I have a CA Hesse Centurion. I bought it at a fun show, didn't pay much for it and want to make it work. What it does is it will shoot a rd,good ejection(about 10 ft) but the next rd will stove pipe. I took some good pics of it with the empty case sticking out of the ejection port but my photo server (zoto.com) is down for maintenance or I would post pics. The case mouth is facing towards the rear of the rifle. I read some posts that said extractor and spring need replacement or it could be the trigger pack in the lower. I don't see how it could be the extractor/spring if the first rd ejects well and I don't understand what in the trigger pack could cause this. Anybody have any answers? Thanks |
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If I understand your post correctly, rounds you manually chamber fire, extract, eject, and feed the next round. Then, when you fire the next round, it stovepipes. If so, my WAG is that the barrel is not pressed into the trunion far enough. Test: 1. With an empty rifle, cycle the bolt as if you were chambering a round. Use feeler gauges through the magwell to measure the space between the bolt head and the bolt carrier. Record this measurement. 2. Load one round in a magazine. With safety applied, chamber that round as you normally do. Remove magazine. Use feeler gauges through the magwell to measure the space between the bolt head and the bolt carrier. Record this measurement. 3. Fire that round. Measure and record bolt gap again. 4. Load two rounds in a magazine. Chamber and fire the first round. The second round should have been chambered by the rifle. Apply safety. Measure and record bolt gap again. Clear rifle. Ideally, all of your measurements will be the same or at least within a couple of thousandths of an inch of each other. IIRC the ideal bolt gap is 0.018", with the tolerence range of 0.020" to 0.004". I'd bet your measurements will be on the smaller side. I'd also guess your measurement for step 2 is larger than the others. If your bolt gap is too small, oversized rollers may bring your rifle within spec. Past that, it's competent HK'smith time. All of this is just a WAG based on limited info. I could be very wrong. Good luck, Karl |
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You could have a loose grip housing (seated against the receiver) that is allowing the ejector to slip under the spent case at ejection, and the spent case is getting knocked off as the spent round makes contact with the live round in the mag. To correct this, pull the grip housing and stick a shim (sticky back Velcro will work) on the top of the receiver shelf. This will take the front slop out of the grip frame to the receiver (where it sits on the shelf). Now before you call it good, pull the trigger housing out for the grip housing and shim the front of the grip housing where the front/bottom of the trigger pack touches the bottom of the grip housing. With the housings correctly installed, the selector will be a tough fit to go back in, and the grip housing front section will not wiggle up and down on the receiver. Now back to the 10’ spent case ejection, the correct ejection of the rifle should be 20' to 30'. If the upper shims do not correct the problem, then you will need to check the BC gap (should be around .013,), or even worse, have to clean up the chamber and it's flutes. |
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First off thanks for all the replies. Second while I know KA3B would love to have a project like this I will not sell it to you  Now for the measurements.Dropping the bolt/carrier inti the receiver and letting it lock in itself, I got a .007-.008 measurement. After assemblying and cocking it using the handle and letting it slam home I got the same measurement(.007). Chambering a rd from the mag with it on safe gave me the same result(.007-.008). The fire one get one jam that I was talking about at the begining was from a mag and not loaded indivdually. I guess it could possibly be the ammo I was using(surplus Indonesian,has PT.PINDAD PERSERO) on the box. I don't want a rifle that would be sensitive to ammo though and think it should run on anything(as these should). The ejector bar in the lower has some side to side play. Could that be it? With just jerking on the grip housing while it is mounted to the rifle it doesn't seem to have any play. All the empties that fired have great flute marks on the brass. If anybody has a collapsible stock I found this great assembly/disassembly link: http://www.mg-42.net/G3_Rbuttstock.htm |
With the chamber empty, bolt locked down with the hammer fired against the back of the carrier, the gap should be in the .012-.014 range. Plus rollers would solve this problem.
This is the scary part since the messurement should be .002 to .004 greater that the empty BC gap with the chamber loaded. With the same messurement both ways, this means that the chamber is fully swollowing the round (the round is loose in the chamber), instead of the face of the bolt pressing/keeping the round tight in the chamber against the chamber shoulders. Bottom line is that the barrel needs to be pulled, the barrel breach set back for the correct head space with the exsisting chamber (not the BC gap), then the barrel reinstalled for the correct BC gap. Hope you got the rifle real cheap since it's going cost a few hundred to have the barrel pulled, correct, reinstalled, and then the upper refinished. |
007-008. is still in "spec" .010 -.012 is "ideal" spec range. Your saying teh rounds only eject 10ft. they should be slinging out at mach 17 and 20ft+ ! since its a century/hesse job id check the following Bolt gap- as you did, charge,let fly,pulltrigger. check. you can swap out to +2 or +4 roller,s nad or a New LP(locking piece) make sure nothing is binding,,see below- scope rails check,,rollers etc make sure you dont have a broken or bent recoil rod or spring make sure your ejector and spring arent busted/broke check teh ejector make sure it is riding high enough into the bolt carrier grove make sure the grip frame isnt setting to low.(part of the above issue) mag's and ammo- check these make sure they are riding to high,to low, or to dirty. clean and re clean that chamber area! use a good lube. last resort if its that bad,, as said above you'll need to re seat the barrel,,whichis gonna cost some $$$ and you may as well toss the cast pos reciver an dget a inspec one and start over with a new build. |
I spoke with a guy who builds HK rifles and converts SP89's for law enforcement. He said that the ideal bolt/carrier gap is 0.017" with 0.010" being the minimum when installing a barrel. He indicated he sets the gap at 0.017" when he does the work. I just located the G3 manual in PDF form and read that anywhere from 0.004" to 0.020" gap is acceptable if the rifle functions properly. Mine is getting close to the 0.004" mark and it functions properly. When the bolt-carrier gap gets below 0.004" a good gun smith can press out the barrel, rotate it 180 degrees and press it back into the trunion. That way they can reset the proper bolt/carrier gap and headspace. The front sight won't do you any good being pointed toward the ground, so the gunsmith has to remove the front sight assembly, rotate it 180 degrees and silver solder it back on the barrel. Like Dano523 pointed out, the rifle will need to be refinished. The guy I spoke with charges $200 for the work. You may want to contact Century Arms about the problem. The gunsmith I spoke with about HK rifles will not work on anything built on a Hesse receiver. Maybe someone else on this board knows someone who does work on rifles with Hesse receivers. I have heard of people having good luck with rifles built on Hesse receivers after being set up properly. The tough part is finding a good gun smith and getting everything set up just right. If it works, it does not matter what name is printed on the receiver. 
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Again, with the chamber empty, then loaded, the B/C gap needs to increase by a few thousands. Without this increase showing that the bolt face is wedged against the back of the case rim, and not just against the back of the barrel alone (round is loose in the chamber), you have a round/rifle not head spacing correctly, and chance having a case over stretch and blowing at ignition, ending up with the receiver ballooned or even worse coming apart in you hands/face (read plus 45,000 PSI of gas pressure release back into the action). But hey, it your life, and I guess the best we can do it to just hold your beer.  |
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