Seating Scenars into the Lands?

[djskit]

After a slight miscommunication with my gunsmith – I have a new 308 that is chambered to seat the bullets into the lands. Rather than have him modify the chamber to jump, I thought I’d take this opportunity to learn something new.

Bartlien 5R 11.25 twist barrel, Surgeon action. (I’ve tried 3 level of charges of H4895 and 3 levels of charges of R15 and shot some scary tight groups with Varget, but way too slow)

My best fast load has been:
Win Brass w/ a .330 redding bushing
BR2 Primers
45 Grains of R15
2.85 OAL
155 Scenars

But that has only given me .75 MOA for 5 shots over 15 shots (all groups right at .75 for 100 yards)

My chrono says they are pushing 3000 but I am skeptical at that – what I’ve done lately is get real world dope and back into the speed but have yet to work this load out at distance.

Based on my measurements , I am seating the bullets about .115 into the lands.

QUESTION: What variable should I change next? Seating depth? Is .115 too much, just right or not enough? What about the neck busing?

 

[MitchAlsup]

Re: Seating Scenars into the Lands?

I use a 332 neck bushing for 0.002 in neck tension in untrimmed Win brass.

Anything more than 0.005 is too much into the lands (ok, maybe 0.007-0.010); my opinion. The reloading press is where the compression should take place, and the 0.005 just guarentees that the bullet will be touching the lands after temperature and tollerances add up in the final firing position.

 

[psinclair]

Re: Seating Scenars into the Lands?

Dont give up on the Varget and dont think you have to jam them to get good results...I shoot that bullet in 4 different .308s all seated off the lands. If your loading 2.850 COAL and seating into the lands bring it back to 2.730. Even if you lose a little velocity those 155s will perform nice at 2850fps. Remember it is a .308.

Try testing for accuracy at 300 meters. One hole groups at 100 are fun but may not tell the whole story.

Good luck and keep us posted, Pat

 

[308sako]

Re: Seating Scenars into the Lands?

.

 

[djskit]

Re: Seating Scenars into the Lands?

Thanks guys - just the feedback I was looking for.

Plan: Shoot groups at 300 - assess.

Shorten OAL in increments to get to .005 and assess.

I'll report back...

 

[Wil]

Re: Seating Scenars into the Lands?

I jump em just fine.... worry not

155 scenar
Win/BHA Match brass
47.5gr Varget
210 primer
2.240 (from ogive)

fits in my AICS mags & chronos at 2900fps

real world dope aligns with this chrono reading as well.