AR 15 in .204 Problems

CWeeks

CWeeks

New member
I had a bullet do this last week during some load developement and thought the rifle was dirty so I would clean it reall good and that would cure my issues.

Well it didn't and it chopped 3 more today. The only thing that I have changed is the cleaning process a little but do any of you guys know what the heck is going on, and what is causing this. And what do I need to do to fix it?????

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It is putting the cases into the chamber but it is almost like it is closing too fast. I am not sure what happened but it really iss annoying and will get very expensive to keep chopping cases.
 
Sorry to hear of your difficulties with the new 204 Carl.
There is a lot of knowledge and experience here.
I'm sure you'll get it solved soon.
Keep us posted.
M
 
Most of the mags I use are either Colt, DPMS, or Brownells and I've never had a similar problem..

It looks like the cartridge may be tilting upward too quickly and would be a magazine problem..
 
A slight change in seating depth can give you issues like that. A little shorter COL could help a lot. It looks like the tip of the bullet is striking the top of the chamber before the rim of the case is free of the magazine.

What is happening to you is not unheard of with the .204 Ruger. Magazines, how the lower receiver holds the magazine, overall case length and chamber-mouth design can all cause this.
 
Thanks Dan for the PM. I will defenantly take advantage of your offer. I will be out of town this next week but may try to send it to you. GREAT GREAT customer service, thanks Dan.

Mike,
Thanks for that explaination. Now I have a few questions more for you. All the rounds previously shot out of this upper were seated absolutely as far as they could be and still fit in the mag. The last 2 weeks were seated a little bit farther in and they are having this problem. I do nt measure exact COL's so I could not tell you that info but it seems that if they were working at longer lengths why would they be having problems with a shorter COL?
 
I've had the exact same problem with my DPMS in .204. I haven't had any problems since I shortened he COL to 2.245 and made sure that every round has been fully resized for a good chamber fit. I run them all through a Wilson chamber gauge. All problems were within the first 100 or so rounds. I had good mags: Colt and CProducts. Good luck, and let us know how things worked out. George
 
Vartarg217(George),
Well I have the same GI mag that I had for my .223 upper before I sold it. I had no problems with it and love it. And I am right at 140 rounds through this new upper and never had a problem until last week. Actually I have a 20 round CProducts mag that would not feed right at all. It saw 3 rounds of use and ruined 3 brass and it has not been back out of my bag since.
 
I have not seen in the post as to whether or not you are full length resizing. It just looks to me as if the rounds are entering the chamber just a bit over size then being bent when the bolt slams home. They all look like the problem is happening at the same spot. Just a thought.
 
I had a very similar problem when I got my first AR. I was using brass that had been shot in my Ruger bolt gun and the chamber was a little different. I finally had to sand my shell holder down so I could get the brass just a little bit farther into the die. I needed to bump the shoulder back just a tad. With new brass I didn't have this problem.

Jimmy
 
I had the same exact problem that you show in your photos. I had taken my magazine apart and when I put it back together I inadvertently put the spring back in upside down. After putting the spring back in correctly the problem went away.
 
Quote:


Mike,
Thanks for that explaination. Now I have a few questions more for you. All the rounds previously shot out of this upper were seated absolutely as far as they could be and still fit in the mag. The last 2 weeks were seated a little bit farther in and they are having this problem. I do nt measure exact COL's so I could not tell you that info but it seems that if they were working at longer lengths why would they be having problems with a shorter COL?



Like I said earlier, there are many different things that can cause this exact same problem, a little longer COL is just one of them. If your upper did not do this in the beginning, then something had changed. That is one of the reasons I mentioned COL. If the upper was working at first, then probably something else had changed: 1) You could have changed magazines, or even dropped the magazine that had been working fine, and bent the feed-lips. 2) You could have changed bullets. A bullet with a different profile may feed differently than another bullet that worked perfectly. 3) Lower receivers make a HUGE difference. When I first started building 204 uppers, I was fortunate enough to run onto this problem right away. My initial problem was my design of the chamber-mouth, but while trying to figure it out, I found a BUNCH of things that had an effect on causing this problem. Once you have the correct chamber-mouth, the lower receiver is the next most likely cause.

In my shop I have several lower receivers that I use just for testing uppers. One of them will shoot .204 Ruger ammo flawlessly in almost any case. I have a different lower that if the upper isn't perfect, you will get the exact case damage that you are getting. I now use that lower to test ALL 204's that leave my shop.
 
Makes sense a mag could cause the problem as well. But I do not remember bending dropping or anything like that to the mag. Thanks to all you fellas for the help. A new mag may be in order if the problem is not fixed after it is worked over a bit by Mr. Carey.

Thanks Mike for the great info. Gives me a lot of things to look at and test if the problem persists.
 
Man I hope you get it fixed in the next month buddy, so It will be right when we head up to you! Still planning on the end of august aren't you?
 
That's pretty wierd. Hope that Dan can get it figured out for you Carl. You might just have to dust of the old Stevens. She probably feels neglected... /ubbthreads/images/graemlins/smile.gif
 
I had similar problems including failure to chamber new round with my Bushmaster .223 when it was new. I was using loads worked up for my bolt action rifle, longer col and lighter powder charges(IMR4198). Switch to H4198 and ball powders 748 H335 H322 BL-C9(2) col 2.2 worked like a charm ever since.
 
Well the saga continues. Now I am completely confused cause I took it out again this week and shot some and it worked properly. Same rounds as before all loaded at the same time and now it is shooting fine.

Dan has contacted me and offered to make things right. +1 for Dan. But he is not accepting PM's for some reason right now. So Dan if you read this please PM me or get me an email address I have some more questions.
 
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