Need Help

[Drof]

My 8" barrel ar15 won't fire half the reloads I feed it. I want to use this recipe as when it shoots its very accurate and clean in my can. 8.8gr Lilgun and the 240smk. I had a few clicks when shooting th efirst time and thought maybe the brass was a tad too long so I trimmed all brass this time to 1.35 and loaded this load again. Same deal. When I let the bolt slam home, then try to fire "Click" is all i get on half the rounds I feed it. The other half fire fine. When I do this I let th ebolt slam home on the round usually once or twice more then it will fire the round.

Heres the ? Do i have a tight chamber or a bad FL die. When I look at the brass after the first or second click, it has a shiny spot on one side of the shoulder leaving me to beleive the trim lenght had nothin gto do with it, but either my chamber is slightly tight in one side or my die isn't resizing completely. Its a redding. I was going to buy some factory corbon ammo and see what that shoots like, but haven't found any. If it feeds\functions\shoots correctly then it's my die, if it doesn't then its my chamber right?

Any advice is appreciated. Brass was formed from new 221

[LouBoyd]

You really need to give some though to what's happening in YOUR AR. Having a "click" doesn't at all say what happened. Looking at the indentation of the primers on the cases which fired and those which didn't will tell you a lot. You said you handloaded the ammo. Who cut the chamber and headspaced it?

There are several reasons why an AR-15 might not fire. You should be able to figure it out with careful inspection,
Possible causes.
Solid primer strike with normal indentation
---defective or contaminated primers

Weak primer strike
--- excessive headspace
---------ammo too short for the chamber
---------chamber too long fore the ammo
---tight hammer pivot pin pin
--- improperly installed hammer spring
--- binding firing pin
---excessive lubricant around firing pin
--- excessively hard primers (unlikely)

No primer strike
-----bolt not fully locked
------ insufficient headsapce
-------bullet seated too long, preventing complete bolt closure. (jammed into lands).
----bolt locked
-------- severely excessive headspace - firing pin cant reach the primer.

The 300 Whisper is supposed to headspace between the bolt and the shoulder but it could be hadspacing between the bolt and the case mouth or the bolt and the bullet ogive. Make sure that's right by using a marking pen on the case and see what's tocuching.

There are other possibilities. At least rule out these by careful inspection of your ammo which you have not tried to fire, which you fired successfully, and which did not fire.
At least take the upper off and insert some of your unfired cartridges into the chamber and make sure they seat smoothly. Wit no ammo make sure the bolt locks smoothly. with the lower separated form the upper make sure the hammer falls smoothly. Make sure the firing pin moves smootly in the bolt carrier.
Is your chamber's throat depth sufficient for the 240 SMKs? Overall length isn't the only criteria. Ogive shape matters too. Corbon subsonics use 220 grain SMKs. I'm not saying the 240's won't work, it depends on the throat of your rifle.

Of course be careful when checking live ammo to see if it chambers properly.

[este]

All good info and you should follow it.

[320pf]

Drof,

What do your primers look like?

You might have a headspace problem. Try forming and trim to length some brass from 223 cases. When you make brass from 223 cases you can set the headspace a bit long and then shorten the headspace until it all fits to what is best for your rifle.

Here is the procedure:

Set the forming/resizing die about 0.05-0.06 off the shell holder and form a case. This case will probably not let your bolt close. So then screw the die down a bit and check the case again until the bolt just locks and goes into battery.

This brass should have the correct headspace and go bang every time you pull the trigger. If it does not, then you have a problem with the rifle itself.

You can test this with primed ONLY brass. DO NOT PUT ANY POWDER OF BULLET IN THE CASE!

I hope this helps and Good Luck

320pf

[Drof]

Thanks for helping me figure this out guys.

The FTF rounds do have pin dents in the primers, they are just no where near as deep as the ones that fired fine. After hitting the bolt release and a second fail, I noticed the shiny area on one side of the case shoulder on every round that did this. Every one that failed, fired on either the second or third attempt. I don't check every round when reloading, but I did check 4 or 5 by both dropping them in the chamber to verify how easy they fell in and out. No problems. I even hand cycled 6 rounds through from mag to ejection. all fed all ejected. I load to 2.20" with the 240smk. and new 221 brass trimmed to 1.35". I sized all brass all the way to the shell holder. This is the same lower that ran the 5.56 upper with out one failure to fire. Same upper rec, bcg and bolt. Sent the entire upper to have the 300 barrel installed and headspaced to that bolt\bcg. They said they test fired it fine, and sent it back. I could understand it being over head spaced except it really seems that after smashing the round in the chamber once or twice it fires, that seems to be too little head space, or the case being slightly out of spec. I guess I took the lower fore granted as it worked fine with the other upper, and hasn't left my possesion. I haven't yet check the the firing pin. Hopefully the additional info will shed some light on things. Thanks Again

[mstarling]

Just a guess ... if you have set your reloading dies too close to the shell holder, the length of the case from the back of the rim to the shoulder may be too short.

This could allow the cartridge to go too far into the chamber resulting in the firing pin not being able to stike deeply enough into the primer to ignite it.

OAL may be OK ... but the shoulder may too far back.

I'd try necking some new brass with a measured space between the top of the shell holder and the bottom of the die. Start at about 0.035". Try to chamber a case and see if the bolt fully closes. If it does not, decrease the space between the shell holder and the bottom of the die a few thousandth at a time. When cases just chamber, reduce the space between the shell holder and the bottom of the die by no more than 0.003" and form a hand full of cases.

Load and shoot them.

If they work OK, you've solved your problem.

Only way I know to fix the cases already sized is to neck them up to a larger diameter (like 8mm) and then size them back to 0.308 at the correct length.

I actually had this problem with a 338-06 Mauser bolt rifle. Drove me nuts finding it. Must have had to toss about 100 cases in the process.

Good luck!

Mike

[Gpz1100]

as to finding cor-bon ammo...midway has some in stock

[Drof]

I will try out some corbon factory 220gr ammo this weekend. If it functions like it is supposed to, I will feel more confident there is nothing wrong with my headspace or chamber and that the flaw is in my reloading items(brass) or processes. You guys have provided alot to check if that is the case. Thanks again.