New Rifle for F-T/R < Reamer? >

[Alexander-M]

While evaluating my options to select a new rifle (custom build) for F-T/R, and reviewing the NRA High Power Rules for F-Class, Target Rifles:

3.4 F-Class Rifle –
(b) F-Class Target Rifle (F-TR) - A rifle restricted to the chambers of unmodified .308 Winchester/7.62mm NATO or unmodified .223 Remington/5.56mm X 45 NATO cartridge cases.

. . . it appears to me that a custom reamer that would yield a smaller diameter chamber to allow for neck turning may not be permissible. Is this correct?

Thanks for your help!

Nando

 

[Kakumba]

Re: New Rifle for F-T/R

Technically, you are correct. In practice, this has never been enforced, at least not to my knowledge. However, see this thread for a bit more discussion of the same:

http://forum.accurateshooter.com/index.php?topic=3860505.0

In short, there is a large number of FTR shooters in the same boat as you, all wondering what reamer to use

 

[Alexander-M]

Re: New Rifle for F-T/R

I really appreciate your input, and read the thread referenced by the link you provided.

The reason I ask is because for my new .308 F-T/R rifle build, my gunsmith, who is extremely knowledgeable, procured a reamer with a 0.332 neck diameter. This means I will have to turn my brass to a neck wall thickness of 0.0108 to allow for a 0.001 clearance per side. (Ø0.3084 + 0.0216 walls + 0.002 clearance = Ø0.3320).

Before I embarked on the turning of several hundred (new and fired) Lapua brass I have, I wanted to check to make sure that I would be compliant to the regulations. I understand that in some matches this is not an issue, and that it would be difficult to measure anyway. However, if I were ever asked about my rifle chamber dimensions, I would tell it exactly as I know it to be, and would prefer not to run the risk of being disqualified.

No, no metal has been cut yet as the new action is not due for another three weeks, so there still is time to make a change.

Thank you for your help.

Nando

 

[ballison]

Nando,
I got a reamer from PTG a few months ago that is designed for 185's and Lapua brass. It has a .3412 neck (don't need to turn) and .168 freebore. You made me such a nice ammo caddy, I'd be happy to let your smith use it if you want. Only used once so far.

Bill

 

[Dos XX]

Alex,
That is very small for Lapua brass. Most people go .340, .341, or even .342 for that brass. I wouldn't want to turn that much off the brass.

I personally think .001 clearance on each side is not enough. Might just be me, though.

 

[seymour fish]

Dos XX, Thinking You are right. 1.5 per side on a .0145 neck wall thickness. Seymour Butts

 

[Alexander-M]

Bill,
Thanks for the offer! I will be getting together with my gunsmith next Tuesday, and we will discuss the issues. I will let you know either way.

Russell, (& Seymour-?)
I was concerned about that, but since I am a rank beginner when it comes to this level of brass preparation, I did not raise the issue initially. But after reading several threads, and simply adding (or subtracting) the numbers, I felt that the Lapua brass did not have to be turned down that much to get a uniform neck. I measured 20 cases, brand new and old (fired five times), at three points 120° apart, and the wall thicknesses varied from a maximum of 0.0153 to a minimum of around 0.0140 for both, with more of the new ones towards the maximum thickness.

However, my biggest concern now is to meet the NRA rules that stipulate the chamber to be standard.

As I said, I will meet with my gunsmith next Tuesday and we will decide.

Thank you so much!

Alex

 

[stgw77]

I would use reamer w. min. 340" neck for Lapua brass. No need for tighter. 2 thou total clearance is not enough IMHO. I use 4 thou total for F-TR.

 

[Alexander-M]

I would use reamer w. min. 340" neck for Lapua brass. No need for tighter. 2 thou total clearance is not enough IMHO. I use 4 thou total for F-TR.

Yes, that sounds better to me, as was also stated above: .340, .3412, or even .342 would do the trick.

So you are not concerned about the chamber not being unmodified for F=T/R, which I guess would be closer to SAAMI specs of Ø0.3442 - .002(allowed tolerance) = Ø0.3422?
<< SEE NOTE, BELOW >>

I just measured 10 of my reloads (Lapua brass with 168gr SMK) and there were two groups - Ø0.337 and Ø0.338, and none of the cartridges varied more than 0.0002 as measured at several places around the neck. The reloads would appear to fit in the above chamber dimensions without need for turning - am I correct?


Thanks!

Nando
PS. Sorry about all the questions . . .

NOTE:
I just reread the thread referenced by Kakumba, above, and several posts have been added in the last few days. It appears that the rules 'may' be modified to require adherence to maximum chamber SAAMI dimensions, including tolerances, but nothing about minimum (tighter) dimensions.

 

[Dos XX]

If you don't want to turn Lapua brass, I would say .342 neck.

.340 is neck turn to me. .341 might be gray area, but I would turn for it.

 

[JFTFI]

International matches are talking about checking fired cases to check neck size. As for as I know they have not made a final decision and have not decided on how to check. They will not insert anything into a shooter's gun. I have read that people that shoot internationally make sure they use a saami reamer with the full .3442 neck just in case. I just built my own rifle and used a .340 necked reamer. I turn by brass to end up with a finished outside dim. of .336. So far so good.

 

[boltman13]

This is my experience FWIW. I shoot a tight neck 308 in Hunter Bench Rest matches. I have been using the same 50 cases, Nosler Custom, for 6 years. Lacking a lathe to chuck the cases in I used a Black & Decker battery powered screwdriver in a home made cradle. I rough turned the cases with a Forester tool, and final turned them with a Sinclair tool. It took what seamed forever to do the job, but that was six years ago. I use a Wilson Collet Neck Die to resize the neck minimally and have very little neck tension. I bump the shoulder at the end of the season for the start of the next one. My load is not maximum and I shoot 125 gr bullets. I do not know if I will ever need to turn any more cases. I shoot a 308 using Lapua brass in an Obermeyer designed chamber with minimum SAAMI specks. My rounds chamber easily and I now use a Forester shoulder bump collet die. I may do a full length resizing eventually if I have chambering issues. The thought of neck turning 300-400 cases does not interest me. The therotical increase in accuracy I might get if I did would not in my mind be worth the aggravation of turning all those cases. You may feel differently, and if so go for it.

 

[memilanuk]

When did Forster start making a collet die? Or Wilson, for that matter?

I'm guessing you mean 'bushing'? The only collet die I know of on the market is made by Lee.