.308 Sniper chamber ???

[Bayou]

Anyone familiar with the .308 Sniper chamber??

I sent the following email question to PAC-NOR:

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<span style="color: #000099">Hi,

I'm going to be sending in a Remington 700 barreled action for rebarreling. This will be a target rifle. I've decided on everything I want except the chamber. I want one of the tighter or match type 308 Win chambers but I don't know which one.

Of the wildcat 308s that you offer I'm interested in learning more about the following chambers:

.308 Palma
.308 Obermeyer
.308 AI

Would it be possible to get the dimensions from you for these chambers? Or if not, could you could point me to a web site that has them listed?

Another question is, are there options within a given reamer choice when chambering? For example lets say I wanted to go with 308 Palma but the standard throat is too short for my bullet of choice (168 gr HPBT Nosler CC), could I get a longer throat and if yes would that cost extra?

Thanks, Bayou</span>
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They replied the same day and on a Saturday at that - NICE!

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<span style="color: #FF6666">I've sent the reamer prints per your request. If your going to shoot the 168gr ask for the .308 Sniper chamber, its throated for this bullet. We can lengthen throats on request.

Chris</span>
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I've never heard of a .308 Sniper reamer. Unfortunately Chris didn't include that schematic with the others but I did ask him for it. So just wondering if anyone can tell me anything about this chambering. Wondering how much "tighter" if any than a standard SAMMI 308 Win it might be?

Also in case any others might be interested in the above chamberings thought I would share. I assume since these diagrams are sent free to anyone who asks there are no copyright issues in posting them.

308 Obermeyer Match

308 Palma

308 Ackley Improved

 

[JJones75]

Re: .308 Sniper chamber ???

I'm not framiliar with the the 308 Obermeyer or 308 "sniper chamber but I have had a couple guns chambered in 308 Palma and they shoot factory 175gr ammo better than anything elese in 308 I've had.

From the pring it appears that the 308 Obermeyer chamber has about a .035" shorter throat , that would be benificial if shooting lighter bullets as it'll get them to the lands with plenty bullet in the neck

 

[sniperaviator]

Re: .308 Sniper chamber ???

Ideally you need to pick your bullet, load one up and pick your magazine (if you are going to use a magazine). Also realize that the lands wear so the throat gets longer. Of course, be cautious in choosing how much powder you use, work your way up. You may not want to run the hottest loads if you are loaded close to the lands. You might want to send him a round of your loaded ammo.

I wanted to be sure of using a bullet that would make it 1000 yards. I chose 155 grain lapua scenars (a common choice). You could also choose the Bergers. I use Varget powder which can go up to 47 grains, but the max I load is 46 grains. My AICS magazine can take, not sure about this, 2.89" OAL. So I would load a lapua scenar to 2.86" in my favorite brass and send him that and ask him to pick a throat length that would load this round .01" off the lands.

 

[Bayou]

Re: .308 Sniper chamber ???

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JJones75</div><div class="ubbcode-body">I'm not framiliar with the the 308 Obermeyer or 308 "sniper chamber but I have had a couple guns chambered in 308 Palma and they shoot factory 175gr ammo better than anything elese in 308 I've had.

From the pring it appears that the 308 Obermeyer chamber has about a .035" shorter throat , that would be benificial if shooting lighter bullets as it'll get them to the lands with plenty bullet in the neck </div></div>

Did you tell your gunsmith that you wanted to shoot 175 gr pills when he reamed your barrel? I've been Googleing up all I can find on match type 308 win chambers and from what I've discovered so far you should not be able to chamber 175 gr ammo as the 308 Palma is designed for SMK 155 gr bullets. But my information comes mainly from posts like this on various forums so it may be inaccurate. Also the situation is further complicated by the fact that there is also a 308 Palma 95 chambering resulting from some specification changes in 1995.

But to go on...

In a 308 Palma chamber with a "normal" seating depth the 155 gr bullets should be close to the lands (0.01" - 0.02"). So if you can shoot 175 gr bullets my guess here is that your chamber was throated for the longer bullets, which means you have a modified 308 Palma chamber, or you have your 175 gr bullets seated very deep in the case.

Could you please comment on this? If you can chamber factory 175 gr 308 Win ammo in a standard 308 Palma chamber (or 308 Palma 95) then my other info is wrong. That info came from posts that are several years old and the posters are no longer active so I can't ask them questions. From the dimensions in the diagram (if I'm reading them properly) then it looks like maybe you can chamber a 175 gr factory bullet in this chamber. The throat dimension is listed as 2.317". I'm assuming this is the distance from the case base to the bullet ogive for a bullet seated on the lands? If I seat a Nosler 168 gr bullet so that the bullet base is at mid-shoulder the base to bullet ogive measures 2.929" so it would chamber easily and there is also probably enough room for a 175 gr pill as well. So maybe the other posts are in error.

That's the two edged sword of internet forums: It's great to get lots of opinions but many of the posts are just plain wrong.


Thanks.

 

[JJones75]

Re: .308 Sniper chamber ???

I told my smith that I was going to shoot factory ammo alot and that the Federal 168 was what was prefered by the department I worked for , he said that all mis customers shooting 308 with the 308 Palma chamber were having great success with factory 168 ammo.

I tried a the 175 corbon ammo just to see if it shot decient so I bummed 3 rounds from a buddy and sent it down range , the group was smaller than any 168 ammo i tried and printed 1" higher at 100yds. it felt as if i was seating the bullet into the lands some but the bolt was not overly hard to close just slightly more than normal.

Personaly I'd rather have a chamber on the short throated side and adjust that later if its an issue because its a pain in the ass to shorten the throat as opposed to lengthening it.

What I would do is either find a factory ammo you want to shoot and duplicate it with some dummy rounds and have that sent when the barrel is chambered or seat the bullets you want to load to the depth you want to shoot them weather its to fit the mag or leave max room in the case and sned those

 

[Willys46]

Re: .308 Sniper chamber ???

I had a 308 Palma match chamber to run the 155 seated to the lands and still fit in the mag with room to spare.

I could shoot the 175 but the bullet would be so far in the case I would have little room for powder.

I have had Pac-nor do a couple barrels and I sent them a dummy round with the bullet of choice seated to fit the mag. I told them I wanted it to touch the lands.

When they were done the sent everything back with the dummy round showing where the lands were touching the bullet.

Leave yourself some room to chase the lands...Not a big deal in the 308, but its nice to have a couple thousandths to set the bullet out after a couple thousand rounds and still fit in the mag.

 

[Pink_Mist]

Re: .308 Sniper chamber ???

I am having my barrel chambered, which is best for 175gr SMK through 20" 1-11.25" 5R Bartlein. 1000' ^ Obermeyer? Smaller chamber = higher pressure = smaller charge? What about the throat length?

 

[Blue Streak]

Re: .308 Sniper chamber ???

I have a 95 Palma chamber and shoot 175 SMKs and 185 Berger Hybrids. I use the 185 s for 1000 yd work and the 175 s for everything else. They both shoot good but I like the heavier 185 at 1000.