M305 cyclic problem

DSX

DSX

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I have my rifle set into a troy stalk for the last 2 years no problems, Then cut down the barrel to 18.5 recrowned and tapped a AR flash supresser on, accuracy went from 3 inch using 168 gr win balistic silver tips to under an inch, but it cost me as my rifle went from a semi auto to a single shot deadly when hunting but I want my semi auto back. Now I know I am dealing with a gas issue. I chamber the first round fire and the rifle extracts and ejects the empty case but does not come back far enough to pick up the next round. After hunting season I carefully took the gun apart and figured the gas ports were not lined up or blocked no everything is clear,cleaned and I put it back together went out and shot 3 to 5 rounds semi auto then the gun went back to single shot, after bear hunting I took it apart again this time focusing on the alignment of the gas ports, insuring the troy stalk is shimed against the gas block and everything is aligned and tightened, and the same thing it fires extracts and ejects but fails to feed the next round. Now if this was a C-6 I would increase the port size on the barrel to allow more gas into the piston, but how much, what size of drill bit should I start with of do I need to replace parts to go with the shortened barrel or am I missing something else. It appears to me that with shortning the barrel I have allowed more gas to escape out of the end of the barrel, any body else encountering this when doing a barrel chop,
Thanks Dwane
 
I had that problem, and gave it a damned good lube. I also had some headspace issues from day one, and once I started neck sizing only, I never had another FTF problem. Can't explain why, but it worked.
 
More help please

I was hoping for more of a response seeing that there are so many other guys chopping barrels on this site and alot of expierience obviously the problem is not isolated to just my rifle.
 
Defiantely a gas issue. Have you cleaned the inside of your piston with drill bits? if there's too much of a carbon build up it could affect function. Is the gas system clean? is the piston binding anywhere?

You shouldn't have to open up the gas port any bigger, there's a pile of shorties out there that run fine on a shortend barrel.
 
I had some minor issues with mine as well after it was cut down and restocked. I had to really clean the gas piston out and unsure that all lined up properly. If the barrel was removed to cut down ensure that the gas port in the barrel lines up with the port in the gas block, use a small punch or nail to check alignment from the piston area up into the barrel, you should be able to see the punch/nail when looking down the barrel. Possibly some minor alignment issues cutting off full gas supply to the piston.
 
Exactly the same situation that I had. Chopped to 18.5" added a PWS muzzle brake, put a USGI bolt (thx hungry), BM59 rear sight and sadlak scope mount.

-I first though that it was the warped chuwood that pressured on something; once I got my custom m14cqb from m14doctor that I planned for this rifle I thought that the whole problem would go away... maybe not... It shot MOA with good ammo but the damn thing wouldn't cycle. :mad:
-Had Wolff M14 recoil spring, went back to norinco one, still no go...

At that point I got pissed
-Then I looked closely to the gas system, everything was lined up and shimmed, but the piston and cylinder were rough, knowing that nobody enlarged their gas port for this, maybe it pointed in the direction of those parts.

-I had a smith enterprise gas cylinder and sadlak TiNi piston that I kept for another build and decided to put them on, the cylinder wasn't easy to put on. Maybe the chinese barrel is a little bit thicker or Smith makes their cylinder smaller (for fitting). Once installed I screwed on a schuster ajustable gas plug. Now the rifle actually functionned; 2 out of 10 for AE 147Gr and maybe 5 or 6 out of 10 for the 168gr hunting stuff, still unacceptable. :bangHead:

-Due to the wierd ajustment required to make it cycle, the gas plug was a problem it itself, picked up a Smith enterprise M1a socom gas plug and a normal M14 one, screwed the socom one first and headed to CRAFM without much hope, and low and behold, it cycled everytime. :rockOn: It became my favorite gun right there!

In summary, everything was lined up and put on tight from the start but the bolt didn't move far enough to strip a new round from the magazine (tried 6 of them) New gas part solved the case, perphaps the port size vary from a rifle to another and the wierd dimmension of the chinese piston exacerbate this and creates the problem listed here. A m14 guru may step in to add its 2 cents to this statement
 
Thanks Toyo, I was thinking that perhaps changing out parts of the gas system could be the identifyer, and just to confirm Greg yes I have done everything that you have mentioned had the gun out a Rally today MASTER OF THE PASTURE shoot out here is wainwright and had the gun lubed right upand was engaging targets out to 450meters but single shot and the Tech that removed and lathed the barrel was definatly in agreement a gas issue, Toyo I will try your solution of replacing the gas plug and go from there, thanks so far guys for the feed back
 
Just a reminder, you won't be able to put a US threaded plug in the norinco cylinder, the US one has very fine threads compared to the much coarser ones on the norinco. If you change the plug, you'll need a new cylinder too.
 
toya said:
Just a reminder, you won't be able to put a US threaded plug in the norinco cylinder, the US one has very fine threads compared to the much coarser ones on the norinco. If you change the plug, you'll need a new cylinder too.
Click to expand...

Found that one out the hard way:eek:
 
A lot of people at the clinic's don't understand why we ask them to do the piston check. It is done for this issue mainly. If you shorten your rig the loss of preasure will resualt in cycling issues. Now sometimes it's an undersized piston witch is just factionaly off and with the 4 more inches of barrel length there is just barely enough gas preasure to cycle it properly but then when you chop it you get into issues. To check this remove the gas plug and lock from the gas system. Place your thumb over the now exposed whole. push the piston up into the cavity. Does it drop like a rock right after you let go from pushing it in there? If so look for some other Norinco piston's. If not then check the gas lock. Some times on Norinco rifles the gas lock can be reverised and it's tightening point will change. E.G. 1 side of my gas lock tightens up to the gas system at 7 o'clock and the other side tighten's up at 12 o'clock. Hence there is more gas bleed out room at the 12 than at the 7 so I mark the 7 side with a ding. This is so I know that this is the side I should have facing out inoder for my rifle to function normaly. Lastley is the gas plug. Most of the time's that this is an issue is because people put it finger tight. Not me as I always use the cleaning tool after I finger tighten up the plug to ensure that it is seated properly.
Hope these pointer's help some else out there that might run into these same issues. Also when ever you get a chance you should really attend a Hungry or M14Doctor clinc as first hand knowledge from these guru's really help you to problem solve in the future.
;)
 
Right on Satain, thanks for the trouble shooting tips I will try them out, as for attending one of the clinics it has been on my todo list and is being upgraded to a much higher priority these days, again thanks to the gun nuters chiming in, info on all this and lessons learned on this forum is golden
Dwane
 
cycling issues can be caused by several things but the gas system is by far the first place to look.
Satain mention's the piston drop test, very important. insufficient vacuum in the gas cylinder will cause gas blow by and not deliver all the energy needed to cycle the action.
a vast majority of m14 and m1a owners are not aware of the correct and necessary cleaning procedures for the gas system. Any lube whatsoever is BAD and gas system should be run dry at all times. A new rifle may function perfectly for hundreds of rounds and then one day...... cycling issues. Many suspect a worn out part or some defect in thier cheap chinese rifle. The issue is often carbon build up inside both cavities of the gas piston and the gas plug's cavity as well. Sadlak makes a drill bit tool kit which are the correct sizes for this cleaning procedure..... and are the correct tools for the job. Exact sizes of these bits can be obtained at your local drill bt store for those do it yerselfers. Powmia56 usuallly chimes in here with the sizes of those bits :D :D as i never seem to have them handy by the computer hehehe

if the above does not address the issue...... a careful inspection of the receiver's oprod channel and surfaces that the oprod travels on , as well as the oprod tab and bearing points , for burrs that could cause a minor hesitation in oprod travel. Such burrs can be minor but yet cause enough "hang time" for the oprod to lose the inertia necessary to reload the rifle.
also inspect the oprod guide that supports the oprod tube and connects it to the barrel. if this is overly loose with rotation on the barrel that might affect oprod travel..... it can also be a culprit..... but low on the list of causes.
 
Well guys i have checked all the above with no results, I tried changing the piston out with a high speed one from Fabsports but the original piston out proformed it although gold does look nice but i think it will be going back. still require a USGI op spring to swap out the op rod, how ever I am not seeing any issues as stated buy Doc, but that is not to say once i replace it with something better, ..... I will post when i finally figure this one out. Dwane
 
I may have an answer for you, but not sure how to fix, as I had the same problem...sort of.

I put a new bolt in my Norky. It shot wonderfully, but just like yours, it was rather random as to whether it would properly feed the next round. Rounds would be extracted like crazy, but once in while (shooting cheap Remington ammo) it would fail to load, like it just ran out of energy.

I am thinking about the spring, but rifle functioned fine before. So then I took a close look at the bolt, particularly the underside of it. I took some measurements and bingo...found my problem.

The new bolt has a slightly larger diameter and hence, it rubs more aggressively on the magazine casings. The gas is sufficient to get bolt to cycle, but the friction of the bolt on the casings, particularly a full magazine, causes it to lose energy. The Norky bolt is of course smaller in diameter.

The underside of my new bolt has a really wide swath of rubbed brass (after 50 rounds) while my norc bolt does not have anywhere near the markings and has shot about 100 rounds.

My first response will be to use the pinned 10 round magazines where the upward pressure on the casings is less than the 5 round mag I was using. The next solution will be to to get a heavier spring or to reduce the thickness of the bolt at that area to match the norky bolt.

If you have your old bolt, compare it to your new one and see if they measure differently at the brass abrasion line on the bottom of the bolts.

Hope this helps. :D
 
Well the next step here is to replace the Norc spring with a USGI OP Spring, i have the Match Op rod from Fabrice but waiting for him to bring in the springs, The drop test has checked out and compared to the titanium national match piston the original piston has more compression and functioned better, so I will try the OP Spring next.
 
You might also try a standard power replacement oprod spring and I also really like replacing gas systems with better ones from 762mmfirearms. Ad LOTS of lube to the bolt, receiver interior, operaitng spring, and a light coat on the outside of the oprod where it slides in the oprod guide.

Use a good quality grease. Lubriplate and Superlube work best for me. Either one.

If the rifle worked before, now it doesn't, and the gas system is properly cleaned, it's probably a lube issue.

Finally, do the tilt test on the gun (use the search function). If it binds, you might need to adjust the oprod alignment to the receiver.
 
Well I have her fixed and rocken hard and well I lubed it up with grease nothing then I drilled it out to 3/32 and its working well I now have my semi auto back
 
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