.308 Palma chamber reamer?

M

model14

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What is the difference between a .308 SAMI reamer and a .308 Palma reamer?
Thank you,
Richard
 
Palma Reamer

A true palma reamer is made to minimum saami specs. It is tighter with a shorter throat in other words. I have a Palma 95 reamer by Dave Kiff at PTG, I highly recommend him and his ramers.
 
There are in fact several Palma reamers. There is the '95 Palma, the Bisley 150, and the .308 Gamboa just to name 3. All have a slightly tighter than normal neck and a little shorter than normal throat. All are set up for a 155 grain bullet. The Bisley 150 is dimensioned so that it will accept and safely fire a 7.62 NATO cartridge while the other two may not. The US Veterans team had to modify their '95 Palma chambers (needed longer throats) for the 2007 matches in Canada so the rifles would fire the furnished ammo. We had to use the Hornady TAP ammo and the 155 A-max they used generated excess pressure in the '95 chamber. So, it depends on what bullet you want to shoot and what C.O.A.L. you want to maintain as to what chamber you want to use. A SAAMI chamber will accept and safely fire most .308 bullets loaded to a C.O.A.L. of 2.800 or less.
 
Not sure about the M852 reamer but it may have been for the m852 Lake City match ammo. I think, but am not positive, that that ammo had the 168gr Sierra Matchking bullet and was used as sniper ammo as well as for the M14 rifle in National Match competition. I can't speak for all the Palma shooters but some that I know and chamber for are using the Bisley 150 and .308 Gamboa. The Gamboa reamer is similar to the '95 Palma except that the throat has been changed to match up more favorably with the new Sierra 155gr bullet (the 2156). In short there is no standard reamer for the Palma team, each member can use whatever chamber he's more comfortable with for the time being. That might change early in 2011.
 
Clowdis is right. The M852 was the US National Match cartridge from 1981 until 1996. It was loaded with the 168 grain Sierra. I've not heard of an "M852" reamer but if there was such a thing it would have been ground to accomodate the cartridge. But, since the M852 had the same physical dimensions as the M118 and the current M118 LR, I can't imagine how it would have been different than any other National Match reamer.

Ray
 
Didn't know about the .308 Gamboa reamer. That makes sense though. Sierra, Berger, Hornady, Lapua have all come out with longer 155gr ogives. Some guys said they have used the M852 for the Lapua bullet because it's very long. 1-12" twists are coming in to stabilize them too in colder weather.
 
I switched to a 12 twist about 2 years ago. One of the reasons was the Lapua bullet which is about the same length as the 175 Sierra. It doesn't hurt with the new 155.5 Bergers and 155 Sierras either, although they still shoot fine in a 13 twist. Anyway, I think I'm staying with the 12 twist barrels.
 
Cheechako said:
Clowdis is right. The M852 was the US National Match cartridge from 1981 until 1996. It was loaded with the 168 grain Sierra. I've not heard of an "M852" reamer but if there was such a thing it would have been ground to accomodate the cartridge. But, since the M852 had the same physical dimensions as the M118 and the current M118 LR, I can't imagine how it would have been different than any other National Match reamer.

Ray
Click to expand...

Ray,
I have a PTG reamer that is marked M852, so I think it does exist. Mine has been reground with a tighter neck but I don't remember the dimension.
Greg
 
I don't have drawings here in front of me so I can't be 100% positive of dimensions but you can probably get drawings from someone at Manson or PTG. But for a little background, the Bisley 150 is ground to safely chamber and fire all the modern 7.62 NATO cartridges and the '95 Palma was also designed to fire one of the 7.62 NATO cartridges but I can't remember which one specifically (not Radway Green I don't think). So I would guess that the body dimensions of all these Palma reamers are somewhat similar. The major differences are in the neck diameter and throat. The '95 Palma reamer has about .002 neck clearance on my Lapua brass and the 150 Bisley has about .004 neck clearance. The Bisley 150 has a throat that will allow the old Sierra 155 to sit about .040 further out of the case than the '95 allowing for just a touch more powder capacity. I haven't shot the Gamboa but have chambered for it and I think it has about the same throat length as the Bisley with a slightly tighter neck, in other words a compromise of the two. The M852 should be larger in both body and neck than these three if it was designed to chamber a M14 shooting heavier bullets. I have another .308 reamer called a "match" reamer that I got from Brownells. I've used it in rifles intended to fire the heavier bullets and it's worked pretty well and I'd guess it's pretty similar to the M852. My guess is that with the advent of longer 155gr bullets and the need for more powder in the case that the '95 Palma reamer will become "less used" in the future. It will probably be replaced with reamers with similar body dimensions but longer throats.
 
New 155 sierra

Assuming the new sierra 155 has an improved BC, I would also assume
it has less bearing surface and or longer boat tail. Is the Palma 95
reamer still usable with the new 155. Its hard to believe the change
could be to severe
 
Throat and freebore requirement for the 2156 is within .005 from what I've used for years with the 2155 when loaded to the same OAL. .050 freebore (same as the original 95 reamer) works well.

This all came from my measurements of gen4, 2156 samples late last summer.
I'm sure it will change just as the 2155 did over time due to wear and tear on the dies, etc. I have samples of the first 2155's and have watched the ogive grow over time/lots to be as much as .055 longer. The 2156's are packed away to use for the same obsevations. FYI: one of the most apparent clues is the sharpness of the bottom of the boattail.

The 155.5 reamer I've made up has no freebore, just leade angle. Not really to my liking, but it shoots very well.

HTH

Alan
 
Bob,
To directly answer your question, I have chambered barrels for customers with the '95 Palma reamer who are using the new 2156 Sierras and are happy with the combination. Sometimes we seem to beat these dimensions to death when what we need to realize is that the Palma reamers are made to work with 155 grain bullets and if you're shooting something heavier like 175s or 190s then another reamer may be better suited. Yes, you can shoot heavier bullets in a Palma chamber, you just have to adjust the overall length of the cartridge to suit the chamber throat, but you may have a pressure problem with factory heavy bullet ammo.
 
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