Hi guys,

I wonder if all you accuracy minded gentlemen will tell me who I should have make reamers for this chamber and dies both? As I've said elseware before I have a 1.35" straight tube, 30" 11 twist Lilja 3gr I'm using to build my wife a nice shooting rig. I want a tight neck so I can turn necks. I also am building a 338 Lapua Imp for myself this summer and would like the reamers to be used for this too.

I've not had any reamers made yet so I'm a little green in this area as to what to ask for specifically, especially with getting one to cut the dies too, and wanting to use it far a larger caliber later as well.

All help is appreciated.

Take care,

[ 02-04-2003, 03:01: Message edited by: Brent Moffitt ]

Brent,

Talk to the good folks at JGS, (541)267-4331 and explain what you are doing. They will be happy to discuss this with you and they are knowledgeable and will help you however they can. Keep the lead angle for the throat no steeper than 1.5 degrees and keep the throat diameter no more than .0005 over bullet diameter. Actually, a throat of .0002 or .0003 over bullet would be perfect... Go with a live pilot as well.

Malm

Thanks GM,

Is it recomended to have the die reamer (FL) made to be a certain size smaller in dia. at the base and the shoulder, like .001", 002" or something?

Brent,

How are you going to form the brass?

Generally for FL sizing of the body, I would want the difference between the die and the chamber to be no more than .002. The neck, throat and headspacing are the areas I would be most concerned with. Once I had my brass formed to the chamber, I would neck size.

Malm

GM,

I'm planning on using Troy Newlons die blanks that have a floating bushing in them setup to minimum full length size the entire case, with another to neck size only. Bushings will be used to reduce the neck in dia.

The seating die will be cut from a Wilson blank and is the same straight-line seating setup of the original Wilson dies.

Fireforming will be done with bullets seated into the lands to hold headspace using starting loads to move the shoulder forward. I'll leave a step on the neck to assist as well.

I figure if the case size is brought down just .001" along the length of the body that should give me enough clearance to chamber easily again when needed.

I just wonder if I need to have the die reamer made .001" smaller up to the shoulder or .002" to allow for spring back?

When my brothers 338/378wby was throated for the 300 gr SMK they measured the bullets at .3088" and bullets were too tight. They had to open it up beyond what the reamer had cut with something, I forget what, but it worked out fine just a royal pain in the a$$ they said.

I appreciate your help here, thanks again.

Brent,

.3088? Since you're not going to know what bullet will work best with your rifle, I would recommend cutting the throat based on a conventional bullet diameter of .308. It is easier to remove material if need be, than to replace it.

You are going to eventually neck size this ammo anyway, so it really doesn't matter what your form die pulls the body to initially as long as it is within .002 of chamber. If you were going to FL size everytime then I would think a clearance of .002 would be sufficient for the body where reliable feeding were an issue.

I had a customer who would bring me HIS body reamers for me to use to cut his chambers. These were dimensioned to the maximum side of the specs. His desire was to have as much case volume as possible. Once blown out, he would neck size. He achieved phenominal accuracy and long brass life from this practice and some amazing velocities to boot, God rest his soul...


As far as actual dimensions go, when you get down to the nuts and bolts of building a custom rifle, your desired end results will dictate the tolerance needed to build the weapon.

Regards,

Malm

You might want to consider http://www.pacifictoolandgauge.com

They'll grind the reamer the way you want, and with a floating pilot 300/338 laupa, you can use a 338 pilot for the 338 chamber, then go back and neck/throat sepperately.