Help on ordering a new 7mm RSAUM Reamer

[Tahoe Shark]

I am switching over from my Dasher to 7mm and I have a couple of questions. The new rifle will be for 1000 yd F/Open. I know I can just call and order a 7mm SAUM reamer but this time I would like to get a custom match reamer for my new barrels that are coming in March. I want to get the maximum performance out of the chambering. The action is a Barnard PT (long) . I have turned the necks on Norma brass to .015 and my loaded rounds are .314. Brass is trimmed to 2.023. I am shooting Berger 180 Hybrids.

I spoke with JGS and they said to send in a couple of rounds that are seated to the length I want. I am currently shooting them at a COAL of 3.12" at the lands. What would be optimum for a 7 RSAUM with Berger 180 Hyb. I have no idea where the original reamer for this rifle is or how it was set up.This is where I kind of get lost. I want to make sure that I seat the Berger 180 far enough out and have a range of jam +.015 and Jump of at least .040. I assume that I want the longest length that will allow a certain amount of throat erosion.

Does anyone have a match print or advice for this combination? What reamer specs are the guys like Danny Biggs shooting RSAUM's in the Nationals using? Should I just skip it and get a stock match reamer. If I need to add information just ask?

Been shooting F open a long time but gunsmiths have always done the chambering for me. They still will do the chambering but I would like to have my own reamer this time.

Thanks in Advance.

Tim

 

[Matt P]

Hi Tim
I have a 0.233 FB on mine and it suits both the VLD and Hybrid, if you're not going to use the VLD's you can go a little bit shorter.
Matt P

 

[Tahoe Shark]

Thanks Matt

 

[Alex Wheeler]

Use Saami case specs, go .318" on the neck diameter for .004" clearence. .225" free bore is what I would order if I had to guess. The method I use to make a dummy round is to size a case, I use full length dies that take neck bushings. The bushing will only size so far down the neck. I do not want the pressure ring of the bullet to go past the sized part of the neck. So measure the length of the sized section of the neck. Say its .250". Now back your seating die way off. Place a bullet in the neck and run it up into the seating die. Now screw the seater stem down until it just touches the bullet. If you want to be able to jump the bullet .040" you would screw the die in .210" and seat the bullet. Now you have a dummy with the pressure ring about .040" up from the bottom of the sized part of the neck. JGS will make the reamer so the bullet will touch the rifling at the length of the dummy. Dont worry about erosion too much. Your accuracy will be long gone way before you run out of neck. And not all barrels want you to chase the lands.

 

[Tahoe Shark]

Thank you so much for the help!

 

[kev77]

.220 free bore 4 tho neck clearance on loaded round . 1/30 degree lead angle .

 

[airborne_trooper]

Tahoe Shark are you having a gun smith in the Reno/Tahoe area put your rifle together?