View Full Version : AR15 being way too picky about ammo.

Jamie Young
June 7, 2004, 08:49 PM
I've had this rifle for over a year now and its being incredible picky about my reloads. Last year, I had 3000rds of reloads that ran fine in my Mini 14, but wouldn't feed 80% of the time in my AR. I went over all of my rounds and through my reloading process, to make sure everything was in Spec, and it was. A few months ago I loaded up a few thousand more rounds and tested them in my AR on Sunday. It ran like a bolt action rifle. :mad:

I had 3 Mini 14 rifles with me and every one of them fed PERFECTLY.

This AR has about 1000rds of Factory ammo threw it and it jammed about 3 times with that.

My diagnosis is that this chamber is way too tight or something. The only malfuntion I have with this is the bolt not locking completely up. And when I pull the bolt back... I just shake the gun and the round plops out.

Easy fix?

June 11, 2004, 07:44 PM
I would check the headspace of your AR15 with suitable gauges.

Then, determine whether or not the resizing die you are using is in good shape, in terms of the resized case dimensions it produces. Check also the case length of fired cases and trim as may be required. If you don't have a dial caliper, you ought to get one. Some are as inexpensive as $15. If you don't have a case trimmer, you need to get one. Forster is an old and outstanding brand.

This is .223 Rem:

Since you said you went over all of your ammo, maybe you conducted these tests. If so, that is good. But, did you check rifle headspace?

Finally, you might want to consider resizing your .223 brass to match the headspace characteristics of your AR15. There are several good headspace measuring tools available from the various catalogs. The Sinclair International catalog is particularly good.

A particularly good headspace measuring tool is the Redding "Instant Indicator". This instrument is ideal, if you wish to resize your brass to closely conform to the headspacing characteristics of a particular rifle. Such efforts are said to improve accuracy and will minimize the amount of 'brass working' during both firing and reloading, thus extending brass life.

If your rifle functions well with factory loaded ammo, then you have a clear indication of one or more problems with your reloading process.

June 11, 2004, 08:05 PM
you might want to try a set of small base dies.Most people reccomend them when resizing onced fired ammo(military stuff).You didn't mention the brand ar but you might have a match cut chamber which will be picky about the brass being resized properly.I am sure the rugers are chamber on the large size of spec so that they do feed reliable.Compare one of your reloads to a factory cartridge at the base where the die stop sizing.There could be just enough difference to keep it from chambering all the way.

Jamie Young
June 11, 2004, 10:09 PM
Thanks for the replies.

I have a Bushmaster XM15E2 20inch heavy barrel.

ArmaLube- I have a caliper and trimmer and everything is in Spec. Haven't checked headspace though.

I think RoyP might be on to something. I have a feeling you are right. How do I know if I have small base dies or not? All I know is a I have 223 RCBS dies.

June 12, 2004, 04:25 AM
The question was:

How do I know if I have small base dies or not? All I know is a I have 223 RCBS dies.

The top of the die will be stamped FL SB (Full-length, Small Base)



Jamie Young
June 12, 2004, 10:46 PM
It says FL T on the top of the sizing/decapping die.

It just says FL Die Set 223 on the box??

June 13, 2004, 08:10 AM
The dies are labeled as small base here is a link to RCBS' at midayusa

Jamie Young
June 13, 2004, 11:55 AM
Pulling out credit card now.

I bet that's it.

Jamie Young
June 14, 2004, 07:46 PM
Why are those dies not recommended for bolt actions?

Am I going to go threw the same thing for .308?

June 14, 2004, 08:04 PM
Is it a SAAMI chamber or a NATO chamber? I'd not use a SAAMI barrel on an AR if someone gave it to me.

Jamie Young
June 14, 2004, 08:34 PM
Is it a SAAMI chamber or a NATO chamber?

I don't know... it's a Bushmaster.

Well i learned something new this week. I just ordered new 223 and 308 dies even though I've been reloading with the Full Lenghth 223 dies for years without problems.

I have 308 dies that I haven't used yet but it seems I should have done more research before buying them. Just ordered Small Base dies for 308. :(

June 15, 2004, 06:24 AM
You can get either the NATO or SAAMI chamber from Bushmaster. The SAAMI chamber is tighter, and fine for varmint guns (bolt action, for example) but can cause grief in an AR.

Don't know that this is the source of your problem, but it's worth looking into.