Anyone able to tell me what could cause this?

[physikal]

http://physikal.imgur.com/bullets

"air pulled" 175GR SMK HPBT bullets for my Remington 700 .308
OAL : 2.7970

I am using a RCBS FLSB Die to re-size.

I loaded 50 rounds at the same time. About 3/10 are rough to chamber. About 1/10 do what you see in the pictures. I have to REALLY crank on it to chamber it. If I hammer the bolt forward it usually goes in ok, but then in order to lock the bolt down I really have to put some elbow grease into it.

What I find odd is the fact that in some cases I'll eject the round, then try it again after shooting a few more rounds. And sometimes a round like this will then chamber with no issues.

This is also a brand new rifle with maybe 100 rounds through it. These bullets were originally loaded for my old Remington 788 (not specifically, hence the full length SB die). This new rifle was apparently built by a Dennis Brush, some local gunsmith. Could it be that this rifle is just much more precise and has very tight tolerances, so I'll have to adjust accordingly?

Any help would be greatly appreciated. Thanks!

 

[doc76251]

Re: Anyone able to tell me what could cause this?

Just off the top of my head I'd say the two rifles have a different headspace by a .002" or so.

Cheers,

Doc

 

[physikal]

Re: Anyone able to tell me what could cause this?

Thanks Doc,

But would that matter if I am still running them through a FLSB die?

 

[scotharr]

Re: Anyone able to tell me what could cause this?

I learned the hard way to just start with fresh brass when using a new barrel. I had one new chamber that would not accept brass from another rifle even after using a small base die and setting the headspace back to new dimensions. It still would not chamber and I basically trashed the brass by bumping the shoulder too much and inducing head separations. Use new brass and bump the shoulder .002 after firing and you should have no problems. NOt sure about the scratches, is that from magazine feeding or extraction? Hard to believe the chamber would cause that.

 

[999yards]

Re: Anyone able to tell me what could cause this?

Try new brass and resize it, if it still does it I would say the reamer was stopped too short. Are the cases concentric after firing?

 

[RH4540]

Re: Anyone able to tell me what could cause this?

I've sent dies back to be shortened, because they didn't bump the shoulders of the case back far enough.

 

[LR-WSM]

Re: Anyone able to tell me what could cause this?

Looking at all of your pictures the thing that jumps out at me the most is the rifling marks on your bullets. I'd say that most of the resistance you are feeling is you forcing the bearing surface into the rifling. Rechambering with less effort might mean that you actually seated the bullet deeper into the case on the first pass. The imprints on your case heads and shoulders might be from you headspacing on the bullet causing a spike in your start pressures.

 

[BobinNC]

Re: Anyone able to tell me what could cause this?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: LR-WSM</div><div class="ubbcode-body">Looking at all of your pictures the thing that jumps out at me the most is the rifling marks on your bullets. I'd say that most of the resistance you are feeling is you forcing the bearing surface into the rifling. Rechambering with less effort might mean that you actually seated the bullet deeper into the case on the first pass. The imprints on your case heads and shoulders might be from you headspacing on the bullet causing a spike in your start pressures. </div></div>

LR-WSM,

You may be on to something. My thoughts are that this rifle was cut with a 308 Palma reamer. A true palma reamer is made to minimum saami specs. It is tighter with a shorter throat, for 155 grain bullets.

 

[GOING FOR 2000]

Re: Anyone able to tell me what could cause this?

Fl-size a new case No primer, powder, bullet. if it's hard to close, the chamber is wrong. head space, case length.

 

[doc76251]

Re: Anyone able to tell me what could cause this?

Ahhh you added pictures that makes 1000 words.

In addition to the commentary above RE: the boolets being seated too long it looks to me like the leading edge of your chamber (breach face) has not been chamfered and it is mauling your case and boolet on entry. I can't tell from your pics if the damage to the boolet and the case are in line w/ each other or opposite. It doesn't look like you are into the lands though as there should be more marks evenly spaced all the way around the boolet.

Give your resize die and seater a 1/16th of a turn and try again. If you still have chambering issue there is something else cooking.

Cheers,

Doc

 

[vinconco]

Re: Anyone able to tell me what could cause this?

Are you loading from the mag? If the chamber is not chamfered the resulting damage might add to the hard chambering. Try loading into the chamber by hand and see if the scrape marks are still there.