Pressure on my long time pet load

[Fastestmanalive]

I have been shooting hundreds of this load since I got my Remmy LTR with 1/2'' at 100yrds. 2615 FPS with single digits SD's. This is what I intended to use to get into PRS.

44gn of Varget with 168 ELDM, Lapua brass (regular not Palma) with Fed Match primers. Same powder lot, same primers lot. This is my repeater load with bullets at 2.800 to feed reliably in the mag. Never got a stiff bolt, primers are not very flat, and went over this powder charge up to 45 without issues at that COAL. No matter what the Hornady book might say, most .308 reloader I know would not consider this as an overly hot load either. Many use this charge for 178gn.

Got a new set of Lapua brass. Ran them with an expander mandrel to avoid the tight necks that you have on virgin Lapua's. Knowing I went much hotter than 44gn without pressure, I didn't felt I needed to back up the load to fire the new brass and account for the possible variation of the new lot since it's still the same headstamp (should be minor variation). Shooting them at the range I got the same velocities, slightly higher SD's which is normal for virgin brass but got the bolt stiff on time out of 40 rounds and ejector marks on many of the fired brass.

If this load is too hot with the new brass lot (assuming lower inner volume), why am I getting the same velocities ? That sucks, if I get down in powder charge, I will give up on velocities which a 20'' barrel already limits me for longer distances. Should I retry this load with the once fired ones and see how it goes ? Any other reason than overpressure could explain the ejector marks on new brass ?

Thanks.

 

[maynard]

Weigh your brass to see if there is a difference from the old lot to the new lot. I just weighed a bunch of new Lapua .223 brass, most weighed 93 gr but about 10 rounds out of 300 weighed 97 gr.

 

[Longboat]

Take your new fired brass and drop test bullets into the case (make sure the bullet will freely drop into the fired case).

If they do not, then the neck wall thickness of your new brass is on the thick side and will have to be neck turned to give enough clearance in the chamber to expand and release the bullet.

Lapua brass is thicker than most other brands and can cause this issue.

 

[Fastestmanalive]

Take your new fired brass and drop test bullets into the case (make sure the bullet will freely drop into the fired case).

If they do not, then the neck wall thickness of your new brass is on the thick side and will have to be neck turned to give enough clearance in the chamber to expand and release the bullet.

Lapua brass is thicker than most other brands and can cause this issue.

They are on the thick side for sure, my ball micrometer got 15thou on average. But not different from the last batches and pretty typical for Lapua’s. Rem 700 are not tight chambers normally but will check this out.

 

[Longboat]

Only a 30 second job and then you can stroke that off the list at least. But yeah I would be surprised if .015 would cause an issue with a Rem 700 off the shelf.

I've had 308 Lapua brass come in at around .018 before so thought I would mention it.

 

[220]

Remington's seem to have a tighter chamber have two that if you do not dry chamber from cleaning and leave a little bit of wipe out and fire the gun you can get a tight bolt lift so heavy thick necks could do same