Advice on reamer for new 308 BBl

unibomber

unibomber

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I need to decide on what type of reamer I need for my new Barrel!
Barrel: Maclennan S.S 30" 1/10 twist 4 grove rifle cut heavy profile.
Bullet: 175gr HPBT Sierra MK.
The Obermeyer has been suggested from some of the best I know, But I am unsure if there are different angles involved in certain reamers and If I may have to have one made specific for my BBl.
Any Input is Appreciated:)
 
.308 Obermeyer

The .308 Obermeyer is about as good as it gets.

I used that chamber on a .308 machine rest test rig for years and enjoyed two 1/4 minute (ten shot) groups at 500 yards with it. Both groups were shot with the 175MK, and both groups were shot in testing handloads of others.

Also, I conducted some kind of mid-production test for Federal during those years with a match round loaded with the 175 MK. Two barrels were used at the request of Federal. One was a Smith. The other was a Krieger. The results, after quite a number of rounds, was in the 2" area at 500 yards.

It just doesn't get much better than that.
 
.308m2

Just found the results from the 1997 Federal test. The old memory isn't too bad.............The result of 60 shots in two barrels @500Y was 2.26".

The action was Musgrave. The machine rest was one of several made by Fred Sinclair, with modifications by Hasecuster and Wylde. The Smith barrel was a stainless gain twist. The Krieger was 1 in 13" CM .298-.3065.
 
The .308 Obermayer would be a very good choice, and it would shoot that bullet very well (as well as Sierra 155s, 168s, and most factory ammunition). All of these bullets can be accurately shot at magazine length (2.800") with that chamber, if that is a consideration.

What kind of shooting are you going to do with the rifle, and will you be shooting any bullets other than the ones I mention above?

For the Lapua 155 grain bullet, I find the .308 Obermayer to have too short a throat; it would be nicer to be able to seat the bullet .050"-0.150" longer. The next time I chamber a .308 barrel, I will either use a "Bisley Rule 150" reamer (they have a throat about .050" longer than an Obermayer), or I'll get a custom reamer made.
 
Daniel,
All my target rifles have Obermeyer chambers, in fact Corben1 was the gunsmith on a few of these barrels. My barrels passed the Bisley Rule 50 in 2000 and 2007 without a problem.
 
The AMU uses the M852 reamer as it uses the more popular 11/2 degree per side as opposed to the more steep 21/2 Obermeyer reamer. I have only 3 Obermeyer reamers. The M852 is a bit shorter and diagrams are vailable on the net or from manufacturers.

What does your gunsmith say?

Peter
 
Thanks for the input everyone :) I sure appreciate the help.
I am planning to try and shoot Just the 175 MK's, I did forget to mention that I need them to be mag length of 2.800" for some matches, I am going to shoot F-class & tactical type matches with it. And one of these days I would like to shoot beyond 600M , So that's why I am going 30" BBL.
The fellow that may do the BBl has quite a few reamers already including the Obermeyer. I just don't quite understand how much the degreeing & distance to the lands will effect the bullets:confused::D But this is a big help for sure.
I am wondering if I should get in touch with someone that makes them and see if they could help too.
Thanks again all :)
 
Hey UB, keep in mind, at least for the BCRA tac match, there's not only a weight limit of 8.25kg, but a 27" barrel limit as well -to keep it competitive with factory rifles and not have it become an arms race. Other Tac matches have similar rules.

You still have that AI that if I recall did pretty good for you though ;)
 
Ya I know! But" Someone" had my BBl made JUST a few inches longer for me( in case I might try 1000m F-class):sniper::runaway: So I'm still pondering the length issue a bit. :confused::D
 
Just had an interesting read of "Handloading for Competitions - Making the Target Bigger". One of the observations (pg 196) was that Remington uses a 3 degree, where most gunsmiths go towards 1.5 degree. Rational was that a factory rifle has to feed anything reliably, where most custom rifles have a more discriminating clientele.

Being magazine restricted, you may want the better flexibility to feed anything, especially if you stay with the Sierra 175 (my favorite for tactical). You might want to go with a lesser angle on your next barrel, but that Obermeyer sounds pretty good for now.

For .308, you're only losing @40 fps per inch of barrel - don't sweat it. Cut 'er to 27 (I use 26.5" in F(F)).
 
If your barrel is a 30" blank it will finish at 28" (or less if you desire). The smith will be hacking some off either end of the barrel. To get a 30" finished barrel, the blank would have to be around 32".
 
peterdobson said:
The AMU uses the M852 reamer as it uses the more popular 11/2 degree per side as opposed to the more steep 21/2 Obermeyer reamer. I have only 3 Obermeyer reamers. The M852 is a bit shorter and diagrams are vailable on the net or from manufacturers.

What does your gunsmith say?

Peter
Click to expand...

On my last 308, Rick cut the 1/10 twist Rock Creek barrels with the M852 reamer. Using Lapua brass and 175SMK loaded to 2.845 (mag fed from AI mag) it shot very very well. Np complaints with the M852
 
Another vote for the M852 reamer. Had lots of fun with it in past 308's

Don't get hung up on the 175gr Mk's. You might find the 155's offer you flatter trajectory which is nice when shooting at unknown distances and fits easily into any F class match. The lower recoil is also a plus when shooting timed multiple shot relays.

As always, feed the pipe what it likes.

Do watch that barrel length. For a tactical rifle, that much barrel hanging off the nose will make it very clumsy to shoot from field positions.

27" solves all possible classifying issues. 24" even better.

Jerry
 
Ya the blank BBL is 31.5 " long and will be slightly heavier than the stock 26" BBl, As for the length to cut it I am still undecided, Although I know at 27" it will do everything well,BUT what kind of difference could I expect at 1000m between a 30''& 27" BBL.

Is The M852 a common reamer?
 
The blank BBL is 31.5 " long and will be slightly heavier than the stock 26" BBl, As for the length to cut it I am still undecided:runaway:, Although I know at 27" it will do everything well,BUT what kind of difference could I expect at 1000m between a 30''& 27" BBL.:sniper:

Is The M852 a common reamer?
 
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