ITT we talk about 375 Cheytac reamers

[dttheliman]

Here I have a dilemma , I am building a 375.cheytac , I only want to use the 400gr cutting edge lazers (gen 2), I have 3 new barrels on the way , I have spent the equivalent of a small african countries gdp on an action triggers stock barrels components powder etc etc - here I am at a crossroads no one I speak to has a consistent answer on what reamer / freebore I should be using answers range from .100" to 200", with a couple of around .160"/.170" thrown in - so now my dumb ass is confused and I throw it open to the wider community here whose collective wisdom I respect.

Floor is open

Thanks in advance

 

[Dogtown]

Usually the bullet manufacturer can give you guidance on the idea freebore for a given bullet. Most of the solids I've shot over the years tend to not need a long throat, and in many cases benefit from a shorter throat due to their normally slender profile.

 

[badassgunworks]

Answer is simple . Seat a bullet in case where you want it to be. Send dummy round to pacific tool and gage tell dave how far off lands you want to be and he builds it. You can also pay a 100.00 expiditing fee and get it made in 2 weeks. Also have him take in to consideration that perersons brass is not made to cheytac spects ring diamiter is different thus datum measurent is off on petersons brass by about .011. Have that corrected on the reamer so you dont have pre mature case head seperation. ( its common ) as metric virsion that peterson builds is different then cheytac spects . Or you can purchase just ptg standard cheytac in stock reamer and a 375 throating reamer and throat it as needed .

 

[GIXXER2000]

Do your self a favor and call Robert Vestal of Vestal customs. I am shooting a Cadex shadow 375ct with a Bartlein 34 in 1-7 that Robert re-barreled for me and it shoots lights out.

 

[Taylorbok]

You should be able to measure it yourself pretty easy given you have the proper tools and such. otherwise send in a dummy round.

 

[j-huskey]

Here I have a dilemma , I am building a 375.cheytac , I only want to use the 400gr cutting edge lazers (gen 2), I have 3 new barrels on the way , I have spent the equivalent of a small african countries gdp on an action triggers stock barrels components powder etc etc - here I am at a crossroads no one I speak to has a consistent answer on what reamer / freebore I should be using answers range from .100" to 200", with a couple of around .160"/.170" thrown in - so now my dumb ass is confused and I throw it open to the wider community here whose collective wisdom I respect.

Floor is open

Thanks in advance

Who is going to build the rifle for you ?

Is that person 375 knowledgeable ?

If yes...
Ask what reamer they use,
Ask if they are 400 CEB familiar,
Ask if they have satisfied customers that have used 400 CEB ?

My first 375 was smithed by R.W. Snyder. It chambered a standard cheytac 350 solid load no problem. It chambered a mag length loaded 350 Sierra Match king no problem.
My first 375 rebarrel was done by David Viers. It had a "standard" 375 chamber and started .015 off the 350 SMK at mag length. This was and still is a sub moa rifle.
Used Jamison and Bartram brass with zero issues.

My second 375 was built by Monroe Hildebrand in Shiloh GA. He built it and headspaced it to Peterson Brass using my PTG reamer.
Re the earlier post about Peterson VS cheytac dimension bit us...
I wanted to use both Peterson and Bartram brass, so, we bumped the chamber to close snug on Bartram and normal on Peterson so when fireformed both would work OK.
No problem...
Except that fucking reamer has a short neck....
Recut the chamber with a standard spec 375 reamer where the Peterson brass fit correctly and went forth with it.

I have both CEB and Warner solids. Have the 400 ceb.

Somebody suggested seating a bullet and determine where your throat needs to be. YES....
Seat the bullet to maximize case capacity, not too deep, or you will find unfriendly things as you try to get that upper velocity to push the bullet out "there"...
Then use a throater to get whatever Freebore you decide you want.

You may find it easier to start with a bit less freebore, and see what your bullet and load does, and increase the freebore with the throater as you hunt the upper level of velocity to push the 400 out there.

Short version, rifle 2 cut with the standard 375 reamer is fine with the ceb 352, warner 361, and ceb 400.

That's my .02

Best to you !

 

[dttheliman]

Answer is simple . Seat a bullet in case where you want it to be. Send dummy round to pacific tool and gage tell dave how far off lands you want to be and he builds it. You can also pay a 100.00 expiditing fee and get it made in 2 weeks. Also have him take in to consideration that perersons brass is not made to cheytac spects ring diamiter is different thus datum measurent is off on petersons brass by about .011. Have that corrected on the reamer so you dont have pre mature case head seperation. ( its common ) as metric virsion that peterson builds is different then cheytac spects . Or you can purchase just ptg standard cheytac in stock reamer and a 375 throating reamer and throat it as needed .

If I read this correctly, you are saying that Peterson brass is slightly smaller than say the other brass out there?

 

[j-huskey]

The datum line on the peterson shoulder is .011 shorter than a std cheytac datum line using Bartram or jamison brass.

Shorter shoulder, not smaller. By .011"

Not a problem (at all) if you headspace the chamber on a case. And redding bushing neck size thereafter.

 

[badassgunworks]

If I read this correctly, you are saying that Peterson brass is slightly smaller than say the other brass out there?

So the metric version that Peterson makes is technically a complete different cartridge then the sammi cheytac or should i say cheytac usa chamber designed for us military by pacific tool and gage they have two different ring diameters and two different datum length measurements. so the metric measurement of headspacing is off by .011 being short. Most gunsmiths are oblivious to this fact. Its a simple fix use a new sized un fired case from peterson for a go gage showing slight feel on closing or get metric go Gage from Pacific Tool & Gauge. Or you can create a false shoulder and jam your bullets tightly into lands when fire forming to
correct headspacing issue

 

[timintx]

From my experience stick with Peterson brass or one kind of brass . Granted there are a few dimension differences and I agree with what everybody said,all good suggestions . The chamber it usually fitted to the brass at least from what I was taught. What I did was ,first measure the base or datum of the case , this is the most problematic area of variations of specs. My Peterson measured .632 now a new case should only be expanded when fired .003 may be .004 at most ,so the chamber reamer specs should be .636 to .637 at the datum, same with the diameter at the shoulder and everywhere else on the case . The biggest problem was with the rear diameter and that is dependent on how much the die will size it back down. AB dies work well with the .636 diameter, most of the reamers are around .639-.640 which wont even go in to my AB dies and stretches the brass more than it should. As far as the CEB lazers no special freebore is needed and you can use most all of the weights from 350 lazer to a 425 lazer just because the front of the bullet sets on top of the lands and the sealtite band stops at the freebore entrance, awesome design. Good luck to you .


Tim in Tx

 

[Kinetic Moose]

Here I have a dilemma , I am building a 375.cheytac , I only want to use the 400gr cutting edge lazers (gen 2), I have 3 new barrels on the way , I have spent the equivalent of a small african countries gdp on an action triggers stock barrels components powder etc etc - here I am at a crossroads no one I speak to has a consistent answer on what reamer / freebore I should be using answers range from .100" to 200", with a couple of around .160"/.170" thrown in - so now my dumb ass is confused and I throw it open to the wider community here whose collective wisdom I respect.

Floor is open

Thanks in advance

same boat here, I would order 100 reamer, and then get a throat only reamer, tune it from there,, I think that the ability to adjust your shell fill with the projectile might make for a better sd's ?

 

[j-huskey]

same boat here, I would order 100 reamer, and then get a throat only reamer, tune it from there,, I think that the ability to adjust your shell fill with the projectile might make for a better sd's ?

I'm going with consistent neck tension, 3 digit scale reading, in weighed same internal dimension cases. Jmhe