newbie 308 chambering problem

[greghost]

Hi all. New to reloading I've spent two years reading and watching videos . I'm loading on a dillon 550b with rcbs dies(2 die set). Cant seem to get ammo to fully chamber in my ar 10 b armalite. Also tried in my rem 760 pump gun. Case feeds hard in that also.The case stops short about 3/8" short of fully seating in the chamber.(Hornady match cases)All measurements exept measurement at bottom of shoulder is 2 thousandth larger than the book shows.454(Bullet is .456) jive with specs in reloading man.Loaded ammo:OAL 2.808 Neck at bullet.335Do I need a neck crimp die ?I was under the assumption that the bullet seating die took care of the crimp? Could I have a bad resizing die ? Waiting on a bump gauge,thinking my setup on the resizing die is off?Gun loads and ejects factory ammo no problem.Also disasembled and cleaned the die.I'm leaning heavily on an adjustment problem with the resizing die.Also ammo checks out on headspace gauge.Thanks in advance for replies.

 

[mgunderson]

Sounds like a sizing die set up problem to me.

Can you chamber the brass before sizing and after sizing? Using dillon dies?

 

[greghost]

Resized brass chambers fine.Using rcbs dies.Only after loading powder and bullet does it not chamber.

 

[GLShooter]

Seat the bullet first and then crimp separately. Many of us don't crimp at all in either of those platforms.

Greg

 

[Bill Norris]

Sounds like you need a small base die. The issue is most likely at the 200 line.

 

[joshb]

Bill: From his post about sized brass chambering fine, I’m going the other direction. I think it’s the crimp.
Your “crimping” is most likely bulging your shoulder.
I don’t Usually crimp. A few months ago, I got into loading for my old 30-30 with a tubular magazine. I had trouble with the crimp and my RCBS dies. Too much crimp pressure was pushing my shoulders out.

 

[greghost]

If I let the charging handle slam shut instead of easing it forward it works fine and also eJects fine but I'm still not comfortable with the round sticking, 3/8 out of the chamberIf I ease the charging handle forward the bolt lugs will not engage.With my other guns the round easily drops into the chamber as it should.

 

[Straightshooter1]

Hi all. New to reloading I've spent two years reading and watching videos . I'm loading on a dillon 550b with rcbs dies(2 die set). Cant seem to get ammo to fully chamber in my ar 10 b armalite. Also tried in my rem 760 pump gun. Case feeds hard in that also.The case stops short about 3/8" short of fully seating in the chamber.(Hornady match cases)All measurements exept measurement at bottom of shoulder is 2 thousandth larger than the book shows.454(Bullet is .456) jive with specs in reloading man.Loaded ammo:OAL 2.808 Neck at bullet.335Do I need a neck crimp die ?I was under the assumption that the bullet seating die took care of the crimp? Could I have a bad resizing die ? Waiting on a bump gauge,thinking my setup on the resizing die is off?Gun loads and ejects factory ammo no problem.Also disasembled and cleaned the die.I'm leaning heavily on an adjustment problem with the resizing die.Also ammo checks out on headspace gauge.Thanks in advance for replies.

Your “crimping” is most likely bulging your shoulder.

The bulging at the body-shoulder junction was what I was thinking too. That could be due to the crimping operation or something else with the sizing die (like the setting of the sizing die's expander ball) and/or lack of enough lubing.

 

[Coyotefurharvester]

^^^^ make up a dummy round, no crimp using sized brass that chambers properly. If it doesn't chamber your seating die/bullet seating is incorrect. Make sure primers are below cartridge face before loading, no proud primers. Lyman ammo checker is your friend for AR reloading.

 

[Tommie]

Back the seating die out a few turns. Fully seat a bullet without crimping and see if it chambers smoothly. If so, back the seating stem out and re-adjust the die to crimp the same round (without the seater making any contact with the bullet) and check again for chambering. If all is well then I think you’ve had your die misadjusted.

 

[Coyotefurharvester]

If you are determined to crimp, all the brass needs to be the same overall length.

 

[HandgunHTR]

The advice above is good. One more thing to remember is that in an AR a round should be chambered by letting the bolt strip the round and load (i.e. using the bolt release), not by easing a round forward using the charging handle. If you insist on using the charging handle, the proper process is to pull it to the rear and let it go.

 

[Tommie]

If you are determined to crimp, all the brass needs to be the same overall length.

Crimping is not a bad idea when loading for an AR-10

 

[358WCF]

A quick thought on crimping... If you absolutely must crimp, are you seating the bullet so the cannelure is even with the end of the case? Does the bullet have a cannelure? A roll crimp wont do good things to the brass if there's no place for the crimp to go. Crimp just enough to roll the brass a little bit. More is not always better.

 

[acloco]

post a picture of a round loaded by your equipment.

 

[snert]

The advice above is good. One more thing to remember is that in an AR a round should be chambered by letting the bolt strip the round and load (i.e. using the bolt release), not by easing a round forward using the charging handle. If you insist on using the charging handle, the proper process is to pull it to the rear and let it go.

!!!!!!!!!! THIS !!!!!!!!!!

 

[greghost]

Ok guys have decided to get small base die as I'm shooting a semi automatic.(RCBS) should I get roll crimp or taper crimp dies in your opinion and why?

 

[NZ_Fclass]

I load 308 match ammo on a Dillon 550. They are a little different! Ensure the FL die is sizing right to the bottom. It can look as though it is in the correct place, due to the case ring - the moving part. Check it again. Some dies will push on this ring and fail to size far enough down. I dont think that I have tried RCBS, but my Forster dies just clear the ring. Some dies are too short to allow the locking ring to be used on top of the die holder. BR for instance. You can use the lock ring under the die block. Works fine. If you are sizing correctly, you should not need to crimp. The neck tension will hold the bullet. The other guys have mentioned small base dies - you could use a Redding small base body die as a second sizer - they are a useful bit of kit.

 

[fkimble@charter.net]

I'm with Tommie. Back your seating die out a turn or two. Sounds like your case mouth is hitting the end of the die and bulging the case body at the shoulder junction. You can usually feel the buldge if you run your thumb and pointer finger up the case. You said your sized cases chamber OK so you don't really need a small base die. If you shoot range brass it's good to run them through a small base die the first time to be sure they will fit your chambers. Shot a M1A XTC for many years, never needed a crimp.

Frank

 

[Doom]

The seating die performs a roll crimp which should only be used on a bullet with a cannelure. It sounds as though you are pushing the the mouth of the case back towards the head. That expands the case body at the shoulder. You should be able to measure the difference if this is happening. Read the instructions carefully on setting up the die. If your bullets don’t have a cannelure do not crimp with the seating die.