Savage 12 Palma Chamber Length

[mlcasmey]

Folks. Decided to try my hand at Palma with an off the shelf Savage 12 Palma. My understanding of a regulation Palma round is this. A .308 WIN case loaded with a 155gr SMK Palma Bullet. Manufactures aside, I assume all dimensions are the same and yes I know Lapua uses a small primer.

I took a .308 WIN case and a 155 SMK Palma bullet and put it in my max depth gage to see how far the bullet would end up being off the lands and grooves. I was stunned. When I removed my test case and placed the bullet back in, it almost fell out. It barely went down into the neck 1/16 of an inch. Sierra says that a bullet should be seated in the neck a min of .80 dia for min neck retention. I then marked and pushed the bullet into the case using .80 dia. The difference was close to 1/4 inch. I could not believe that Savage would make a "Palma" rifle that seams to be chambered so long that a bullet loaded safely would have 1/4 jump. I've never had a target rifle from .223 all the way up to .338 with more than a .035 jump using SMK bullets.

Am I really missing something here.

Savage has of course said I can send the rifle back and have the chamber checked against their standard, a Factory Lapua Palma round. Since I don't own one, would it not be essentially the same case base to ogive as the one I just made?

Mike.

 

[jo191145]

Might want to take a peek at this page. i had to look it up out of curiousity. Not my area of expertise.
http://www.6mmbr.com/palmabasics.html

I could have sworn Palma did away with the sierra rule long ago. Seems they did more than just that.

From memory dating back years the 155gn Lapua Scenar has one of the longest bearing lengths in the 155gn class. A-Max might be longer or close.
The Sierra Palma bullet has the shortest bearing length in that class. I can't recall the exact story but that bullet was designed to overcome a specific problem years ago between American and international Palma competitors. That specific problem, whatever it was is long gone.

Your case base to ogive will measure differently with different bullets. Keep that in mind for future reloading.

The fact remains your chamber was cut long enough to require longer bearing surfaces. Not saying Savage was correct in doing so. Just the facts.

Two years ago I bought a Savage take off barrel in 308W from one of thier law enforcement models. I have absolutely no trouble reaching the lands with a 155 Sierra Palma.
Go figure. A scary accurate barrel with 155 Berger VLD's.

You can try jumping or buy modern bullets or send it back to Savage and hope they find it faulty.
Personally i'd buy better bullets, practise awhile and get a nice custom barrel to screw on that rig.

 

[mlcasmey]

Thanks. Since my Savage has a 1:13 twist, I'm restricted in the weight to no more than 175gr. I think I am going to have to shop around for the bullet with the longest bearing lenghts. Talked to the bullet Techs at Sierra and they said I should be able to find a node where powder charge and jump produces a good pattern as long as I maintain the minimun .80 dia bullet seating depth in the neck. Problem is my only way to adjust now is to increase the jump even more to find a node. It will just be a new experience tring to find a node so far away from the lands. I've gotten spoiled by SMK's. Every caliber I've used them on so far I've found the first node between .015 and .035 and usually between .020 and .025. Makes testing pretty easy and fast.

Sounds like I have a lot of tuning ahead of me. More fun on the range!

And your right. If all else fails there is always Pac-Nor ...

Mike.

 

[Mikey_P]

Mike - I'm also shooting and reloading for a Savage 12 Palma. Based on what I am seeing, it sounds like your chamber may have an issue. If I seat a Sierra MK (2155) to just touch the lands, the bullet is into the case mouth approx. 0.20 inches - a much greater distance than the 0.06 you are seeing. I'll try to post some exact measurement numbers tomorrow, I don't have my notebook at hand.

Also, I use my S12 Palma only for midrange 600 yd matches. I've found the Hornady 168 AMAX at 2860 fps to be reliably accurate with the factory 1:13 twist barrel. If you don't feel like sending your rifle back to the factory, you might want to try this bullet - the bearing surface is a mile long . However, at my velocity, I don't think this bullet will get you to 1000 yd. if you're shooting true Palma matches.

Mike

 

[the punisher]

I have a 6.5x264 F class Savage Factory rifle and it has a long jump to the lands, and others I have talked to has the same thing. Kinda like a Remy, long throats for long bullets......

 

[memilanuk]

I've got two 12 Palma Rifles... one of the very early ones (like first few off the line), and a later one from 2010.

To the best of my knowledge (conversations with the factory engineers), they use a Palma 95 chamber reamer (purchased from JGS, fwiw). 95 Palma chambers tend to be pretty short in the throat, relatively speaking, compared to most other .308 Win chambers. Its possible they've changed things since that point... but its also important to remember that the 95 Palma reamer was designed around the older 2155 bullet, not the 2156. The 2156 has a *much* shorter bearing surface (as does the Berger 155.5BT Fullbore)... hence the newer 2011 Fullbore reamer which is now more commonly used in full custom rifles.

I went back through my notes that I keep on seating depth for every barrel I have. For both barrels (produced ~2 years apart), a Sierra 155MK (the new 2156, not the older 2155) seated to a hard jam in the lands using a Hornady LnL comparator tool and then measured with a Sinclair .30 cal insert (steel, with tapered hole vs. the aluminum with radiused hole of the Hornady/Stoney Point version)... measured 2.095 in one and 2.100" in the other. OAL was approx. 2.876"

Tonight I locked the comparator down 2.100", the longer of the two measurements, put the bullet in the modified case and pushed it out to solid contact with the comparator. I took a sharpie (very high tech!) and marked the bullet at the case mouth, then pulled it out and measured (roughly) the bearing surface from the mark back to the front edge of the boat tail: 0.167"

Considering that you'll probably get best results with somewhere around 20-30 thou jump, so that puts it that much further into the case... 0.190-0.200" worth of bearing surface - plenty.

Its also interesting that Sierra recommended 80% of bullet diameter worth of bearing surface in the neck... usually the old school thumb rule is more like 50% (minimum), and from personal experience I *know* the Berger 155.5BT Fullbore will shoot well enough to be competitive in F/TR, much less Palma - with as little as 0.090" bearing surface in the case neck, and jumping 0.045" to boot.

How/why your particular throat seems so long is an interesting situation... with a bullet seated to jam length, what is the OAL (base to tip)? If its significantly longer than the 2.876" listed above... then yeah, you might need to send it in or else look for a bullet with a) more jump tolerance (i.e. Berger 155.5) or longer bearing surface.

 

[mlcasmey]

Thanks all. I am going to try a couple Berger bullets. I hear, like some of you have said, that they have longer bearing surfaces. The 175 LR Match looks promising, but everyone is out of stock right now due to matches. I'm really going to try and not send this back unless all else fails. I will not get it returned until it's almost winter here in Minnesota. Moving down to 50% bearing surface may give some better results.