failure to extract

[CavTrooper]

Ok, just got this M53 kit together with a Project guns bolt. I have cut a new spring to what I thought was a good length to start with. Fired several rounds and got a couple of doubles of the tripod and some failures to extract the spent cartridge, the next cartridge feeds partially into the chamber and the gun jams. I cut 1/4 coil off and tried, same thing, cut off approx. 2 coils total and still getting the failure to extract if the belt is loaded. If I put one round in the belt and fire, it will extract that cartridge. Put two cartridges in the belt and it will jam. Does anyone have a trouble shooting start point? I am at about 15 coils on the spring, the face of the buffer screw has been recessed. Again it wil extract on a single round feed from the belt but doesn't extract the first round is two rounds are in the belt. I also replaced the feed cover and bolt with another, everything is oiled well also. I didn't replace the feed tray as I didn't have a spare with me. With the return spring removed and the bolt installed and retracted I have about 3/16" between the buffer housing and the return spring extension and the end of the buffer spring is hitting the extractor sleeve. Help........!!!!

[JBaum]

So, it leaves the empty shell in the chamber (fail to extract)? The extractor does not grip the bolt well enough, and the bolt goes rearward without taking the empty shell along with it?

You're asking very specific questions, so we need very specific details. You have three links empty at the start of the belt so that the belt doesn't jam internally in the top cover when it tries to advance, right? You've read an operating manual so you know what to do and how to do it, I presume.

More details are needed, whatever the problem is, it isn't serious.

[CavTrooper]

First, I appologize for the confusion on my part, the problem is fail to eject, not fail to extract. As far and understanding the operation and how to load etc. yes, I understand.

CT

[oakrodent]

Will it eject them when you cycle it by hand? When you switched out the bolt, did you switch out all of it or just some parts? Also try a spring from BRP and quit messing around with the original. Also what sized booster cone are you using? Going to need lots of info for something like this. It could be a lot of different things.

Also try this.
Take the bolt out of the gun. Stand it up on its butt. Remove the booster cone assy. Push down on the barrel sleeve and let go. The barrel should move to the rear fairly easily and snap back into place. If it doesn't something is wrong. The barrel is binding up from the heat of the first round and not letting the bolt to cycle completely. The barrel has to move freely!

[JBaum]

Sounds like inadequate recoil, failing to have the bolt hit the buffer to eject when there is extra friction
resistance due to the next cartridge. If it ejects a single cartridge, the recoil spring isn't the problem. You want as much recoil spring as possible, so long as the rear of the bolt must hit the buffer to eject the cartridge.

Check the nozzle hole size. Are you shooting 8mm or .308? .308 takes a smaller nozzle size.

Oak meant to say to take the flash hider and nozzle off, stand the gun on the muzzle and push the barrel bushing on the floor. If the receiver bounces back up quickly (due to the recuperator spring), that's good. If it doesn't bounce up quickly, there's a problem with the recuperator. Dirt, incorrect assembly, weak springs, etc.

Do the above test and post the reply.

If the pressure plate is bent downward, the next cartridge could be causing friction, draining the recoil strength away from the action. The semi version is running on borderline energy levels as it is. It doesn't take much to cause a problem.

[CavTrooper]

I did the barrel/recuperator test when I built the gun and just tested it again, works great, not sluggish. Ejector will eject an unfired round if chambered and cycled. Booster is 11.5mm and I'm using a fresh can of AIM Rommy 8mm. Bolt slides freely, extension doesn't interfer with buffer spring. I have a friend who told me he had to weld about .030" on the end of the ejector "spoon" to get it to eject reliably. I did place the bolt assy onto the buffer and noticed that the ejector does not extend to the max., it is about .020" or so below it's full extended position. I measured 5 other ejectors and spoons and they are all the same length as the ones I've tried in the gun. I switched out the complete bolt assemblies, one has the V2.0 conversion and the other has the old style. The ejector button is free to slide and does so if I tip the bolt back and forth and it seats flush with the bolt. I'm going to try fitting the bolt and grip stick etc. one at a time to see if there is a bind someplace that I haven't found before. I wonder if I need to try another buffer? i tried a different top cover but not a feed tray, maybe that is next also.

CT

[CavTrooper]

Just tried placing an empty cartridge in the bolt and using the buffer (all extrenal from the gun) to push on the extractor button. If I push on the extractor button with the buffer or anything else, the cartridge pops out partially, still caught by the extractor at an angle, slight push either way and the empty either clears the bolt or locks back into the bolt squarely. I tried this with a couple of bolts, one with the extension welded on and one without. I did not slam or bump the ejector, I just pushed on the back of the bolt until the button bottomed out in the bolt body. Seems to me that what I've been seeing is that the cartridge is partially ejected and the next round is being picked up but the empty is still in the way, the empty jams into the barrel and the new round can't chamber because the empty is still in the way. Maybe the feed tray and or the feed cover combination is the problem. Should the empty be completely ejected before the new round is being picked up and feed in? Or, is the new round supposed to help push the empty out???

CT

[CavTrooper]

That last question about the empty being ejected first was a dumb one, I know better. My mind is numb from thinking about it half the day and screwing with it the other half.

CT

[JBaum]

Typically, the shell is ejected with such force that it damages itself on the front of the trigger guard. I think you've found your problem. I think it would be better to correct the bolt or buffer, rather than screwing with every ejector bar that's ever put into the gun.

[CavTrooper]

Well, I've gone through everything I can. I milled .020 off the slots in the bolt carrier which gives me an exact line to line lock with the ejector button, extension and plunger with all bolt parts in the compressed/retracting state. I checked for interference of the bolt and rails, the bolt will slide to lock if I just slide it down the rails with one finger. The grip stick does give some resistance due to hammer drag on the bottom of the bolt but the hammer has another .2 inches of clearance if completely compressed after the sear engagement. I slicked up the bottom of the bolt and the contact surface of the bolt. The buffer spring does not interfer with the bolt extension. The recuperator and barrel function great. I am trying an 11mm booster and still using the Romy 8mm ammo. A friend gave me some Yugo 8mm to try also. I off the the range tomorrow to see what if any progress I've made. I even replaced the top cover and feed tray and will take spares of each and the extra bolt and buffer. Maybe I'll take the camera also and if the problem isn't solved I'll post a picture of the misfeed.

CT

[CavTrooper]

Ok, finally got to the range. I took some Romanian and some Yugo 8mm ammo. The steel case Romy would not cycle well, I think it must be light ball. The Yugo worked well, finally got the ejector to function. I shot 20 rounds without a hangup. Now, I'd like to find some 11mm and 10.5 mm booster cones. Does anyone know who has any for sale. I can drill out and weld a bushing into a couple of 11.5mm if I have to but, I'd rather just buy the correct ones. My idea is that if the Romy 8mm is light ball then maybe a smaller booster cone will allow it to cycle more reliable.
Another question, who has done the buttstock conversion for the full length spring? Did it make any difference? Does the BRP spring help prevent spring bind?

Thanks for the help.

CT

[CavTrooper]

Ran a 10.5mm booster cup on my 42 for about 50 rounds of Romanian 150 gr. without an ejector problem. Changed back to a 11.5mm and now it feeds like a champ, feeds Yugo heavy ball and Romanian light with no hickups. Just took a little exercise to loosen it up I believe. Now on to build no.2.

Thanks for your input.

CT