28 February 2023

A Bad Day At The Range

 is still a pretty good day.

It was a bit disappointing, however. I took the new-to-me AR upper and the lowers that I had built for it out to play, and the darn thing just would not feed from either of the lowers or from either of the magazines. If I bounced the darn thing on the polymer magazine the round would go in, but otherwise nada.

So I packed it up and took the Glock 36 to the pistol range next door and put 50 aluminum cased rounds through it. It had one FTE, not a stovepipe, where the ejector just slipped past the rim of the empty and didn't get it out. It came out with no issues, and that was the only problem with the aluminum cases.

Next, Range Partner had brought a couple hundred old reloads with him, so I helped him burn them up. I put 100 rounds through the 36 with only a few issues due more to light loads, I never had a squib but there were one or two that didn't go bang with enough authority to properly cycle the slide.

The verdict: since changing the barrel I haven't had a single problem with the gun that could not be attributed to ammo. Also, I managed to ring the steel consistently although I couldn't consistently hit the small swinging targets. So, I still suck at this game, but not as bad as once upon a time. Dry firing helps.

Once I got home I consulted the Internet regarding my AR issues and found that I have an M4 upper receiver mounted to an AR barrel. The difference is in the feed ramps. On the plain AR the feed ramps are integral only to the barrel extension (the rear-most part of the barrel that is fluted to mate with the bolt; so much to learn with the AR platforms); the regular AR has a flat front wall on its upper receiver with no ramps and the ramps on the barrel extension stop at the outside edge. 

On the M4, however, the feed ramps continue down into the front wall of the upper receiver and the barrel extension ramps are slightly deeper so it makes a smooth transition between the ramps in the upper receiver and ones in the barrel extension. The idea is that the M4 will feed better at faster cycle rates or with rounds bigger than the standard 5.56 which, mine being a 6.8, is. 

 The result of my setup is a ledge where the ends of the AR barrel extension ramps meet the ramps in the M4 upper, and that combination with my lowers and magazines tip the rounds downward just enough to catch that ledge. Funny thing is, the original setup (I bought just the upper, the guy I bought it from kept the lower to put a different upper on it) worked just fine.


 The cure is to either swap to an M4 barrel, or take a rotary tool or round file to the barrel extension ramps to match them to the receiver ramps. There is some debate as to whether it's a good idea to do this while the barrel is mated to the upper. I think this may be a job I'll leave to a gunsmith.

In other news, it looks like I may be picking up a .357, so I have that going for me. The last .357 I owned was a Taurus that I got from a "friend" over some money he owed me and then later found out that it had been lifted from his mother in law's truck, so I had to give it back. 

I am more certain of this one's ancestry, so that won't be an issue, but it is a lightweight S&W that is...let's say, somewhat uncomfortable...to shoot a lot due to the recoil inherent in a powerful cartridge and a light gun. I'll put some .38 through it for practice and keep the high power loads for business.

It's been too long since my last range day, but now that the weather is getting better I will work at improving that.


4 comments:

Angus McThag said...

M4 ramps in the reciever with rifle ramps on the barrel isn't the end of the world.

If you think about it, a rifle worked fine with no cuts in the upper. A flat wall would stop the round just as well as the little scallop.

If your round is presenting low enough that it won't chamber from hitting the bolt release from locked back; your problem isn't the ramps, it's the presentation.

The M4 ramp came about because original configuration, now known as rifle ramps, caused stoppages from the rounds hitting that flat wall. This was from cycle speeds and the bolt coming forward too fast for the magazine spring to get the next round all the way up to the top of the feed lips.

It almost never occurred in semi-auto!

But! A heavier buffer should cure it if you're cycling too quickly.

Cutting your own ramps in the barrel extension also works, I've done it myself twice now. With the barrel mounted so I can match them to each other.

I would do both, actually. Check your ejection angle, over gassed leads to faster cycling. If the brass is going noon to 3, you're over gassed. You want 3 to 4:30ish.

Larry said...

It's almost if you are speaking a language that I should understand...over gassed...ejection angle...

Complete AR noob here. I think my problem stems from the fact that I am using polymer 80% lowers and the magazines sit a bit lower in the mag wells than they would in a fully-formed aluminum lower. The 80% lower already had the mag well cut, all I had to do was drill the trigger, trigger pin, hammer pin and safety switch holes and mill out the pocket for the fire control group, so I'm pretty sure it isn't anything I have done wrong.

FWIW, the tip of the projectile is hitting exactly at the outer edge of the barrel extension where the lip is.

My biggest issue right now is I think a bit of dremil work with a small carbide bit would fix me right up, but I'm too much of a coward to do it for fear I would ruin a barrel and/or upper receiver. I would think barrel mounted so you can match the ramps would be the best way to go as well, but I have seen the arguments both ways (the issue seems to be that if you remove the anodization from the upper you will open the door to corrosion problems).

At the same time, I hesitate to think there is anything seriously wrong with the upper since it did work fine on the previous lower, and it works great as long as I can get it to feed.

As I said, AR noob, it's my first one and I don't want to screw it up by doing something stupid to it.

Thanks for dropping by!

Larry said...

Doggone it McThag, my fat fingers deleted your comment by mistake when I tried to publish it. Teaches me to do this on the tablet instead of on a real computer.

Thanks for the info, the ejection seems to be coming back and not forward, at least all the brass was behind the firing line. I'll try to find some of the magazines you mentioned and see if they work, if nothing else I only have two and I'll need some more. It might be a minute before I get back down to FL, but I really need to.

Thanks for dropping by!

Angus McThag said...

If it's ejecting TOO far back, like 4:30 to 6:00 then you're undergassed and everything is running too slow.

It's harder to cure.

It's also not a huge bother to get a different upper receiver without the ramps on. Easier than working on a Subi!