I've put together a rifle for my nephew from a bunch of extra parts, one being a 26" WOA match rifle barrel. I cut the barrel to 20" to make it a bit handier but have kept the original rifle +2" gas system. Got to the range and while it shoots very accurately it seems to be undergassed. Using crappy Wolf steel case ammo to sight the scope, it would either leave the spent case in the chamber, or eject and not load a new round. So it is short stroking, probably because it's missing six inches of barrel in front of the port. I didn't expect this to be a problem, but here it is. It would lock the bolt back with a couple 80gr Amax loads I had on hand but these are single feed. PMC ball with a different mag seemed to work a little better but I think is on the edge. Definitely not a vigorous ejection cycle. I want him to be able to shoot inexpensive ball ammo (not necessarily steel case junk) in it so I need to make it function better with it. New barrel or shorter gas system are out for now, I need to deliver it in three weeks. He'll be hunting coyotes and plinking with it.
So far some options I've come up with are to open the gas port a little (how much?), Wolf reduced weight buffer spring, lighten the recoil buffer (currently rifle A2 style), remove some weight from the M16 style bolt carrier, anything else I'm missing? I really don't know how much weight to remove from the reciprocating assembly to make the improvement so am looking for guidance/experience there. Reversible modifications preferred but I'm looking at everything right now. Appreciate any insights.
Frankly it's no surprise it ended up undergassed with that combination. That's an important thing to consider before shortening an AR barrel, and if you do, you need to be prepared to open the gas port.
You'll need to buy an assortment of wire gauge drills and open up the port in small increments until it runs right. Don't rely on someone else's guess on port size, best results will come from verifying what works on your rifle.
Changing springs, weight, etc to non-standard parts (especially for someone who doesn't know ARs well) is a band-aid fix around the gas port issue and sure to cause confusion and/or problems later.
Fair point, but my available time for iterative testing is short so was hoping parts swapping at the range would be faster. I decided to go to the mountain and spoke to the man himself, John Holliger at WOA. He wasn't surprised either. He was very helpful and indicated that the port was already larger than normal (~.105") to support the 2" longer gas tube that is fitted, but that I could go as far as .125" which would match the hole in the gas block. I don't think I'll have to worry about a burr because the bore scope shows there is plenty of erosion around the inside edges of the hole. Hopefully I can find all the sizes that I've failed to return to my number drill assortment.
Using slower powder and heavier bullets would also help with the current system but I don't want to handload all the kid's ammo.
I understand that you want to use cheap & somewhat low pressure ammo, but the easiest things to do, aside from opening the gas port size some more, would be to try some genuine 5.56 pressure ammo with a carbine buffer, & with a reduced power recoil spring if you have it available.............it might work.
Obviously, it's not likely to work with the low pressure ammo though & as Yondering said, fixing the gas port size is the surest fix.
Unfortunately, there no book or pat set of conditions that anyone can recommend, just the directional changes discussed already.
Actually don't want to use low pressure stuff. Just surmising that this steel cased Wolf is based on result and friends comment. It definitely has faster than optimum powder for this tube length. The PMC 55gr stuff functioned the action but ejection was not brisk, so I think it is right on the edge as it is now. I'll check diameter of the port tonight and open it five or ten thou based on where it is. I also realized I may not have the gas block centered, so I will verify that with the bore scope if possible.
I think it was the standard PMC stuff. I don't consider it low pressure per se but understand where you are going. Hopefully with a little bigger hole, it will handle everything. The adventure begins....
I think it was the standard PMC stuff. I don't consider it low pressure per se but understand where you are going. Hopefully with a little bigger hole, it will handle everything. The adventure begins....
The PMC 223 ammo is definitely lower pressure than their 5.56 ammo. Same for Federal. If you tune a rifle to just barely work 100% with the 5.56 rounds, often it won't cycle completely with the 223 stuff. Yours may have ended up in that situation from the sounds of it.
Opening the gas port is still the best option regardless.
Tip for drilling the port (assuming you have at least a decent vise and drill press) - find a drill bit that matches your current gas port size, and set it in the hole when you clamp the barrel in the vise; that makes it easy to visualize when the hole is perfectly vertical. Then to locate the hole, hold that same drill bit backwards in the drill chuck, inserted as far as it'll go. When the drill bit shank will slip into the gas port hole, you've got everything aligned correctly for drilling to the next size up.
The barrel is set up in the mill at this time, centered as best I can with what I have on hand. Waiting on a set of gage pins to arrive from Amazon. Needed those anyway and when they arrive I'll finish the setup. Current hole size is some where between .098 and .104. I'm missing a couple number drills from my set so will have to wait on the gage pins to know for sure. Plan is to open it to .110 and see how it does.
John said I could go to .125 which matches the gas block hole. He said removing one or two coils on the spring or a reduced power spring wouldn't hurt, but lighter buffer was less likely to. I think somewhere between .110 and .125 will work and if it doesn't I'll chalk it up to a learning experience. I can always plug the current port and re-drill in the standard position, just to see what happens.
Quick fix is a light BCG and lighter spring, but as noted, its just a bandaid.
But it will show that the gun can work.
I"d open the port until it works, then open it one size more.
I"d only put an ADJ block on if needed after that.
I"ve fired so little of factory ammo of any type I have no clue whats up to speed so to speak or not.
But I'd try it with factory Gold medal match 69s for one, if it functioned with that, I'd be somewhat worried about opening the port personally... might lean to spring or lighter BCG, the bolt that used to? come wiht Colts that had the bottom milled off should be lighter....
We can keep Larry Root and all his idiotic blabber and user names on here, but we can't get Ralph back..... Whiskey Tango Foxtrot, over....
I doubt you'll over gas a +2" rifle gas system for 223 pressured ammo. Drill it, just don't go through and hit the bottom.
Ha! I thought of that and will have a piece of drill rod in there to know when I get through. Otherwise sure as you know what, I'd be getting plenty of gas from my dual ports!!
Your drill press doesn't have a depth stop adjustment??
MM
Index milling machine and yes it has a stop adjustment that is a PITA to setup. No sense in screwing it up, the rod will let me know when the drill bit breaks through and prevent it from going too far.
if you can' t make it work with just drilling it out and have to buy a new tube, let me know, I only shoot heavier loads, 68 and up generally and usually pretty dang warm and reloaded. I"ll bet I can work it just fine. Plus never hurts to have more of Johns work.
We can keep Larry Root and all his idiotic blabber and user names on here, but we can't get Ralph back..... Whiskey Tango Foxtrot, over....
I usually run into issues on the other end, it seems that most rifles tend to be overgassed...but my first inclination wouldn't be to make non-reversible mods to set a rifle up to work with the cheapest, crappiest, out-of-spec, low pressure ammo I could find.
If you were to just clean up the port and make sure the rest of the gas system is clear, after that there are different buffers to play with, it seems like that would do it.
I usually end up with a heavier buffer, but then I've never fired a round of Commie steel cased 223 ammo, but I wouldn't expect much from it if I had..
"Supernatural divinities are the primitive's answer to why the sun goes down at night..."
I usually run into issues on the other end, it seems that most rifles tend to be overgassed...but my first inclination wouldn't be to make non-reversible mods to set a rifle up to work with the cheapest, crappiest, out-of-spec, low pressure ammo I could find.
If you were to just clean up the port and make sure the rest of the gas system is clear, after that there are different buffers to play with, it seems like that would do it.
I usually end up with a heavier buffer, but then I've never fired a round of Commie steel cased 223 ammo, but I wouldn't expect much from it if I had..
I think shortening a +2" gas system from 26" to 20" already counts as a "non-reversible mod". LOL.
This problem has nothing to do with typical commercial grade 5.56 barrels being overgassed, which is true but a completely different thing. If you shortened a typical overgassed 16" carbine barrel to 10", you'll find it undergassed some of the time too. (Although I did shorten one 16" DPMS barrel to 10.5" that still had plenty of gas after shortening; that was a good illustration how overgassed it was originally.)
I think shortening a +2" gas system from 26" to 20" already counts as a "non-reversible mod". LOL.
Yeah...there's that...
I don't have a problem with chopping the barrel or drilling out the gas port... talking about the choice of test ammo.
Just sayin that I would set-up the rifle for ammo that was in spec and not worry about whether it fires the worst ammo that one can find. Lacquered cases can tend to stick to chamber walls.
That's likely a better than decent barrel and would shoot real well with good ammo.
"Supernatural divinities are the primitive's answer to why the sun goes down at night..."
Another option is to just drill it to max spec, and install an adjustable gas block, then tune accordingly. You could go from ‘bubba’ to ‘full custom’ that way, LOL
and after all this screwin around you could have just bought a new barrel and be done with it.
Some work with what they already have, others just buy and buy more. Different strokes really, and can generally work both ways.
I think he is so close to it working, other than being stubborn about cheap ball ammo, its almost there....as is.
Anyone cares to send me $100, I'll go buy a new barrel. I'd rather spend that kind of money something else. I could have gone and bought him a $2k name brand build, but what's the fun in that?
I have the equipment, if not the knowledge to find out if this barrel can be made to work. That's why I tinker with stuff. I always wonder why people are so concerned with how much work something might be for someone else and advise they buy their way out. I enjoy the challenge of a problem (that I admit I created) like this.
Just to clarify, I'm not building this to run steel case crap. I was just using some up to center the scope. When I say "cheap ball" I'm talking about Federal Eagle, IMI, Wolf Gold, and PMC brass cased stuff with inexpensive FMJ bullets. He doesn't hand load and is a poor college kid. Plan was I build the rifle from parts I've collected and his dad buys him a case of ball to play with and 100 rounds of "good stuff" for coyotes and other varmints. I get all the spent brass in compensation for my incredible effort.
I appreciate most of the input. I'll be drilling the port tonight and testing on Friday and Saturday hopefully. I will report back with results, good or bad.
if you can' t make it work with just drilling it out and have to buy a new tube, let me know, I only shoot heavier loads, 68 and up generally and usually pretty dang warm and reloaded. I"ll bet I can work it just fine. Plus never hurts to have more of Johns work.
I'll keep that in mind. It really balances well with the full size section under the handguard and that extra 6" missing from the front.
I would not make any permanent changes to gas port until you are sure you understand the issue. If the system is truly undergassed, I would do the following:
1. First, is the gas block self indexing, or fixed in position by cross-pin? If not, check alignment. 2. Have you removed all carbon from the existing gas port? 3. Any gas escaping around gas tube? 4. How many rounds on gas tube? Is tube kinked or fouled? 5. Do you have a standard weight Buffer and spring? 6. Are you running a muzzle device. Depending on type, this can increase gas pressure. 7. Make sure components (BCG, bolt, Mag, etc.) are not dragging.
If you are sure that you are maximizing existing gasses, then consider a lighterweight BCG, and other fixes.
Ran by Cabela's at lunch and picked up a few boxes of different brass cased ball type ammo. Then I couldn't stand it anymore and as soon as I got off work, ran home, picked up the rifle and headed to the range. Last night I pinned the existing port at .101". With the upper set up in the mill vise, I used a drill that measured .110, and dropped it into the hole. I had a dowel in the bore to confirm when it broke through and prevent going too far. The Lyman bore scope showed that there was very little burr on the inside. Put the gas system back on and was ready to go. Got to the range today and started with single loading the mag to make sure it would lock back the bolt. No issues for three single fired shots. Load two and repeat three times. No failure to feed or lock back. Started ringing the gong at the 200yd line with no issues. All cases were ejected about 8-10 feet at 3:30 to 4:00. I tried four factory loads and two handloads with zero issues. I set the target up at 100 and fired five shot groups with each type of ammo. Pic of target attached shows just over 1MOA with the 55gr ball and a bit better than that with handloads from my NMC service rifle. Groups were shot in failing light from less than steady rest with a 40 year old Western Field 2-7x scope. I would expect 25% better results if I actually took my time and had decent glass and a solid rest. Group 1 is on two targets because I couldn't see the first two holes and I thought I was high so I moved down one target. I then remembered I still had a box of the Wolf Polyformance steel cased stuff that didn't run well the first time. It would either not eject the fired case or eject but not load. It functioned the rifle fine, loading the next round through a ten shot cycle, but still would not lock back the bolt. Got quite different report with it as well, I'm pretty sure its loaded with a faster powder that would work better in a shorter gas system. The stuff is crap so I'm not concerned.
I'm claiming success. Ejection was solid but wasn't overly brisk. I could safely open the port a bit more, but I'm going to not temp fate and go with it where it is and I can always do it later if there are issues. Overall I'm pretty happy with it. I think I have less than $275 in the entire rifle by sourcing used and on sale parts, including a used Geissele trigger . Life is too short to use [bleep] triggers. I shortened and crowned the barrel in my lathe, shortened the handguard to clear the gas block, and got it all together and shooting without blowing myself up. Accuracy is excellent for a pile of cheap used parts and can mostly be attributed to the WOA barrel. I think my nephew will appreciate it and put it to good use. If he manages to wear the barrel out, I'll replace it with a take off 20" Service rifle barrel using a standard rifle gas system. When they stop holding the x-ring at 600yds they still have several thousand rounds left in them for shooting 100-200yds.
ball ammo at an honest just over MOA is something to be proud of. its not easy to get that junk to shoot that well. I never shot ball ammo that shot MOA.
We can keep Larry Root and all his idiotic blabber and user names on here, but we can't get Ralph back..... Whiskey Tango Foxtrot, over....
ball ammo at an honest just over MOA is something to be proud of. its not easy to get that junk to shoot that well. I never shot ball ammo that shot MOA.
I thought it was a bit special too. This thing has well exceeded my expectations at close to 3000 reported rounds fired. Again, the credit all goes to John H at WOA, he did all the work on the front end. Funny, the guy I bought it from said it was a good barrel, but I think it's potential maybe was wasted at 26 inches and it wanted to be a national champion 20" SR barrel....
