Donut inside the neck?

[Sniper338]

I got two pieces of brass i found while reloading tonight where the bullet seats in a bit, then feels like it hits a wall and it stops, and WILL NOT seat any further into the case... bullets are only half way seated to the right OAL...


Is this a donut inside the neck that takes inside neck turning to fix? I dont know how in the heck i would have caused it, theres a first time for everything i guess..... brass has two firings on it, this was the 3rd reload... lapua brass...

Kicker is the second reload i found these two pieces of brass hard to seat a bullet in... this time it wont seat... no problems with any of the other brass...


Best i can figure looks like i got 2 pieces to chunk.... aint enough to spend money on an inside neck turner if thats what id have to do...

Cant visually see anything on the exterior of the case that looks odd...

 

[fguffey]

Is this a donut inside the neck that takes inside neck turning to fix? I dont know how in the heck i would have caused it, theres a first time for everything i guess..... brass has two firings on it, this was the 3rd reload... lapua brass...

Snipe338, "I don't know how in the heck I would have caused it". That puts you into a large crowd. I need to know what chamber, I have chambers that will never form a donut. I form cases, before complete forming the case I have to remove the donut.

Other donuts, turning necks, some make donuts when turning necks, my opinion, those donuts are mistakes. After forming the mistake the mistake gets pushed to the inside when fired and or sized.

F. Guffey

 

[jcampbellsmith]

I get donuts with my 260 Rem brass when I full length resize the cases. I neck turn the neck/shoulder junction to remove them.

Regards JCS

 

[jr600yd]

What caliber are we talking about? Here's an example of getting a "Donut". I made some 6XC brass from new Lapua 22/250 brass. Followed the directions for first time sizing, had the little mushroom at the shoulder
and fireformed them. Upon sizing the second time I found the neck had a small step of brass just ahead of the shoulder and about 1/8" up the neck. Cases would not chamber. WTF is this? sizing without the decapping stem and expander ball (Forster BR dies) did size this portion of the neck, cases chambered just fine, using the decapping stem and expander ball produced the step. No matter how I adjusted the sizing die the results were the same. Must be something wrong with the die (Wrong!) I neck turned some of this brass just cleaning up the neck and cut about 1/16 - 1/8" into the shoulder and the problem went away.

Observation: since I was making a new case, 6XC from 22/250 cases, the mushroom did not make full contact with the chamber. Upon firing the first time the case expanded to the chamber and brass flow blew out the 22/250 brass to 6XC dimensions causing the "step" in the neck. Neck turning into the shoulder cured this. If I didn't neck turn the once fired brass two things would have happened. 1. I'd have a lot of brass that wouldn't chamber and therefore be useless or 2. If I sized without the expander ball I force the "step" to the inside of the neck and have a real problem seating bullets to X length.

Like you I didn't want to go thru the trouble of inside reaming the necks. Neck turning into the shoulder cured my problem.

 

[Sniper338]

This is just plain ol lapua 308 brass.... 308 win.. nothing crazy.. thats why it makes me wonder so much...

 

[ARshuter]

I was having the same problem with my 284. Necked up 6.5 x 284 Lapua brass to straight 284. After second firing the donut was there at neck shoulder junction. Didn't happen on all cases at the same time but eventually came on all 300 cases. I resolved this with an inside neck reamer, after doing the necks it has never came back. Didn't happen on resizing happened when I fired. My guess is this was because I chambered this barrel to absolute minimum head space leaving no room for exterior expansion so brass flow had to go inward.

 

[fguffey]

My guess is this was because I chambered this barrel to absolute minimum head space leaving no room for exterior expansion so brass flow had to go inward.

I don't know how in the heck I would have caused it,

That puts you into a large crowd.

Again, I have chambers that will never form a donut, I have never had a chamber that had more room on the inside of the case than the outside.

F. Guffey

 

[Milo 2.0]

A oversized neck dia in your chamber, then sizing with a Redding bushing die will create donuts. Enough firings and the donut will be on the inside of the case also.

 

[22BRGUY]

You might try pushing the donut to the outside with an expander die and then turn it off.