today was an exasperating, yet rewarding morning at the mill. I am making a quarter-rib for the barrel, and the back 3" of the barrel that thread into the receiver is round. It scallops into octagon and that has been the fun! I got a piece of steel 3/4 x 3/4 x 8" long and have been milling it to octagon flat width plus a "lip" that just overruns the adjoining flats about .050". That part was easy, the exasperation comes from then trying to mill the top flat back to the threads on the round area and keep it all flat, straight, and even. Second time's the charm. Now if that NECG express sight will just show up! Had ot make a new front ramp from stock...the one Wisner made with the bottom half not rounded that I had hoped would just slide over and keep the octagon part flowing was cut wrong...I forgot that the round hole had to be smaller than across the flats...oops!!!

Pictures follow as soon as my friend Jeff gets them to me (Email) and I can get them to another friend Jeffe to be posted as a reply here.

What fun.

Rich

Rich,
if you had a piece of pipe the exact OD of the barrel, you could put that in the lathe, cut the bottom of the 3/4 square with a 3/4 ball, clamp it on (or put 2 screws in it way up from THEN clamp it) and take a boring bar and cut the 1.2" or whatever round part... THEN work the octagon in on the mill

jeffe

Is there such thing as 'NECG express sight'?
Isn't NECG hardware produced by ERA (G. Recknagel)? They make good stuff. Blaser, Heym, Johannsen,.....use their components.

Jeffe,

wouldn't that be too easy? I am just following directions.

QUESTION: I am making a brake, removable of course. If I bored the entire hole 5/8" instead of bore diameter +.020" or so is it going to hurt the recoil reduction?

thanks,

Rich

Rich,
you have found my kryptonite... i know jackdiddley about brakes, other than they are loader than... well, yeah...

jeffe

Might not have been clear on the jig setup.. that's an inside turn and bore.

jeffe

quote:

Originally posted by Idaho Sharpshooter:
QUESTION: I am making a brake, removable of course. If I bored the entire hole 5/8" instead of bore diameter +.020" or so is it going to hurt the recoil reduction?

thanks,

Rich

Being oversize on the bore will hurt both reduction and accuracy (turbulance caused when the gas is expanding faster than the bullet is traveling, but being confined by the brake body it can't expand away from the bullet).
You want the brake bore to be tight enough that the bullet will act as a plug in the front wall of the expansion chamber(s). The princapals of brake design are very similar to the design of a silencer, in that you are trying to redirect the largest amount of gas away from the line of the bore. You should try for a 2-3 stage brake, with a large reflection surface(s) and maximum redirection angle.
You can never acheive it, but the goal is 100% of the gas redirected 180^ (could this be why they are so loud, Jeffe Speak up, I'm a long time brake user )

Jeffe, what in the hell are you talking about?????

Rich,

There is some good info on muzzle brake designs on the net, don't have the URL handy but you should be able to google it. As I recall you want about 0.010" over bullet dia. Personally I can't see a removable break. If you need a break, then just leave it on. To me an integral break is the only way to go.

Keep the muzzle dia fairly large, back bore the last inch or so of the barrel 10 though over, and then mill in the expansion chambers with a 1/4, 5/16 or 3/8" end mill, about 1/8" between chambers, and about 1/8" from the od top and bottom of the barrel.

Much easier to make than a removable brake, and you'll be as concenctric as you can get. Also port orientation will be spot on.

Good advice Paul, if you think that far ahead and get the barrel big enough diameter to do so. My next one (bought another Rem 30Express) will utilize a Badger or Krieger barrel about 1 3/8" dia. X 32" long. I think I can now confidently tackle the job of milling the integral quarter-rib, underlug, and front ramp and brake over a week or so. Got the bolt handle welded on yesterday, my knee told me to take today off. Now I know why all old gunsmiths have arthritic knees...chasing the cutter along the lathe and standing for hours at the mill. The most fun I ever had at the shop was making a 36" long drill bit to bore a 45-70 barrel to take a 50 caliber liner for myfirst 50-110 (M1886 Win). It took 8 hours to run that bit/cutter thru the old barel at .050" bites between brushing the swarf off and putting a little more cutting oil on with a paintbrush. I am really liking the looks of the octagon barrel on the Rem M34.

later gentlemen,

Rich