Seating bullets causes the necks to bulge

[Kanttori]

BTW, I'm using 2.2" overall lenght. Slightly under the 5.56 lenght, is it still an ok lenght??

[jripper]

That length should be OK if it is not a light weight (125-130 gr)bullet. When you say it will not extract, are you talking about after firing, or ejecting a live round.

If it is with live ammo, it may well be the extractor. If not...well then there are several possibilities.

[Kanttori]

Ejecting a live round...like these dummies I made...there's nothing wrong with the extractor. I checked it...and even tried it with a new bolt....no live round extraction problems with 5.56 rounds....this is strange...What on earth could cause this?!?

[jripper]

What load are you shooting? It could be that it is not cycling the gun fully (look at my thread on model 1 sales problem). There are several fixes for this.

Also, it is possible that your load is too hot, and the extrator is ripping through the rim. You could tell this, very easily by looking at a fired case.

You could also not have enough extractor tension. This can be improved by replacing the extractor spring or adding a D-Fender ring under the extractor. I have a D-Fender, but have not put it in either of my AR's, as they don't really need it.

[Kanttori]

Jripper,

First I want to thank you for helping me out. Obviously this is a rather quiet forum.

I am not shooting the upper yet. I want to test chambering and extraction before I load real ammo. So all the tests so far have been made with empty rounds (*No primer or powder*). Once the upper functions with the *dummies* I have made..then I'll get down to real business. I'm an amateur so I rather check and test, check and test than go for it an KABOOM. I was thinking that maybe the reason why the extractor doesn't pick the round from the chamber is that it falls too deep...BUT I don't know how that could be possible. The case shoulders should make it stop right where it's supposed to. I'll try to get some pics up...with measures...maybe you could compare those with the rounds you have made and see if there's anything wrong.

I still have faith :D

[jripper]

Hey, No Problem with the help.

I just got into the .300 last fall, and the guys here helped me get through some problems I was having. Last summer I built a house in the country were I have my own range, and can do a lot of chronographing/load work literally out my back door. If it wasn't for this, I think I would not have attempted the .300, as it does seem to take a little experimenting to get it to work right.

But, in the long run, I think it's worth it.

I also don't like to work, and would rather reply to this forum.

Probably a good idea to try the dummy route first, as I jumped right into it, and ended up pulling out a bullet and dumping powder into my receiver (I have become an expert at stripping a lower, due to this happening a couple of times).

What brand Upper/Barrel do you have? Is it a new bolt, or a used one?

Are you dropping the round directly into the chamber, and then closing the bolt, or are you feeding it from a magazine?

As a rule of thumb, in semi autos, you should always feed from the magazine.

I can't picture the front of an AR bolt in my head right now, but it it works like most bolts, the round is designed to come up under the extractor. If it is dropped in and the bolt closed, the extractor may have to snap over the rim, and if the bolt is not worked briskly, it may not do this.

Of course, like I said, for some reason I can't picture what the extractor looks like, and I don't have an AR with me at work.

So, I could be way off, but it is a thought.

The round should not be falling in too deeply, as it should head space on the shoulder, like you said.

I'll keep thinking about this one....

[Turtle]

Hello,
New to the board and to the .300 whisper game -- but I would like to give my 2 cents in the hope it may help someone.

I think there is a headspace problem here on this ar. I would like to make a suggestion. Take a piece of formed .300 whisper brass without a bullet or primer -- hold the bolt back and install this brass into the bolt -- make sure the rim is captured by the extractor and guide the bolt closed holding the case in the bolt with your index finger. You will feel the spring pressure of the ejector trying to push the brass out the ejection port -- that is where your finger will be -- holding it in place. You can do this with the upper off of the lower so you don't have to worry about damaging your finger. Push the bolt all the way forward and then pull the bolt back. If by doing this the bolt closes all the way and the round is ejected then you know the headspace is at least big enough. Assuming the extractor is operating freely -- not frozen and will open with decent amount of pressure -- then we can carry on. (At this point in the post I would assume the brass was ejected if it was manually installed on the bolt.) Next step would be to manually install that same piece of brass in the chamber -- close the bolt completely and see if it will extract. If not then you know your headspace is toooo much. And let me be clear -- headspace is too much for that piece of brass. I had this problem and found that by using the redding FL die with the die set to hit the collet slightly --over(or under)sized my brass -- basically made the distance from the base to the shoulder too short. My fix was to change how I was forming brass -- left the gun alone. You might try this with 223 brass and make sure to size the shoulder a little at a time until the brass with just bearly allow the bolt to close completely.

Sorry for the long post -- just wanted to be clear.
I hope this is of help. If it is not let me know -- I will try to think more on it. I can try talking on the phone if that might help.

John

[Kanttori]

Hello,

Almost a year since I began this thread. I got so pissed off with the upper / ammo not working that I just forgot about it. Now I here again. Still having the same problem..Im off to make a few test shells...be back in 20mins :D

[Kanttori]

Ok,

I made a yet another dummy round..I installed the round on the bolt and helping with my fingers I rode the round into the chamber...pulled the charging handle and the round flew across the room.

Also, I tried an unformed .221 firball brass...with the bolt back I put the case into the chamber, released the bolt..pulled the charging handle...and nothing...turning the upper upside down and giving the case a gentle tap with a rod it fell out without any resistance.

[Kanttori]

here are some measurements

Total lenght of the cartridge: 2.15-2.22 [I have tried various lenghts]
Total lenght of the case: 1.3575-1.3665 [the brass is new untrimmed Remington brass]
Outside dia of the round just after the bullet: 0.328
and just before the shoulder: 0.330
and just after the shoulder: 0.356
and before the rim: 0.373
and lenght from the bottom of the cartridge to the shoulder: 1.084 (measured from the narrower beginning of the shoulder)
and from the shoulder to the mouth of the case: 0.281

I hope someone can help me!

:(