Will a MG shoot cast boolits?

[Paul5388]

That seems to be a big question with many and some will flatly state the micro groove barrel will NOT shoot cast bullets.

Here's a 50 yard group I shot today, while practicing for the next postal match.


I used 7.5 gr of IMR 800X in .357 brass with CCI 400 primers, no crimp and the 250 gr Beartooth gas check boolits seated in the crimping groove. I chose IMR 800X because it has been giving me pretty good groups in some other loads I have tried. The POI was about 6" above the POA, but I was shooting for group and that didn't bother me, especially when they shot into .693", center to center, using calipers this time.

It's on a shotgun receiver and forearm, Bushnell 3-9X and has an "O" ring, but no trigger work.

[Haywire Haywood]

I'm going to quote a line from Veral Smith's book "Jacketed Performance with Cast Bullets".  I hope he doesn't mind.

"Marlin's micro groove rifling, damned by most gunwriters, is in fact the best rifling FORM I know of for cast bullets.  Notice that I said that it's the best form, not that Marlin makes the best rifles."

According to him, a barrel with a high number of relatively shallow lands imparts less distortion on the boolit and therefore is more apt to produce good accuracy.  I would assume of course that it hinges on the barrel being of good quality in the first place.

Ian

[Big Blue]

Paul,
  If that top hole in your target was a flyer, you have one great shooting barrel there. Just curious, was that the first shot?
Don

[Paul5388]

Don,

I know it's totally unbelievable that I wouldn't know the answer to that question, but I don't have any idea which one was first.  What I do know is that there were two boolits that had a moly spray on coating and the third one didn't.

If you check at Handloads.com on the .357 Mag rifle thread, I posted a jacketed group that was .439" and actually hit the target I was aiming at!

[handirifle]

Boy Haywire I bet the boys on the Shiloh Sharps forums will take issue with that fellow.  Last I hear those rifles hold all the records with cast loads, and none that I am aware of are micro grove.

http://www.shilohrifle.com/forums/

[Haywire Haywood]

I wish I had the cash to have a barrel made to test his theory.  He says that a man named Pope back a century ago made a barrel with V shaped lands the intent of which was to minimize bullet deformation.  He couldn't do exactly what he wanted because of the technology at the time.

I dunno, I'm just regurgitating what I'm reading.  Has anyone ever made a "Match Grade" barrel with microgroove or similar rifling?

Ian

[JPH45]

My opinion and a dollar will buy a cup of coffee.......Micro Groove barrels will shoot, they do tend to be picky about what they like in bullet hardness and velocity. They tend to perform better with jacketed bullets. I ain't no Veral Smith, but I know of no Micro Groove barrels shooting cast bullets holding any records. The common type of rifling today used for cast bullet shooting is "Ballard". This is a land and groove form of equal widths with square corners at the root and top of the land/groove cut. The depth of cut is generally about .005"

I am less familiar with Mr. Popes barrels, but it must be said that he was an avid shooter and competitor in Shutzenfest type competitions and held a 200 yard record for 75 years and was a contemporary of Mr. Ballard. A study of Mr. Ballards and Mr. Popes rifling techniques would seem well worth the effort, these gentlemen laid the groundwork that we as casters still use today, 100 years later.

Micro groove rifling is a form of button rifling which was developed to speed production. It matches well with jacketed bullet technology which is what most people shoot, and it serves them well. Unfortunately, (or fortunately as you may percieve yourself)  cast bullet shooters are exceptions to the mainstream, and if we find a barrel that shoots cast well then it is a joy, otherwise we search, hope, or save our pennies to get a real barrel.

[Leftoverdj]

Haywire, back on the old Marlin Forum there was much discussion of this. Seems that one of the gunwriters talked Marlin out of a microgroove BLANK and had a good custom smith finish and fit it with exceptional results. The consensus is that there is nothing wrong with MG, it's the other stuff that Marlin does to the barrels that's the problem. Lotsa folks reported tight spots under where the text is rolled onto the barrel and where dovetails are cut. Seems that Marlin does not mill the dovetails, but broaches them which can displace some metal into the bore.

[mag41vance]

My NEF sb2 .357 mag  has 8 grooves; I guess that makes it MG. It shoots several cast loads very well. One is a 148 gr HBWC, over 2.7 gr bullseye in a .38 spc case. That groups consistently around 1" @ 50 yards.
 The next load is a 150 gr RCBS SWC in a .357 max case over 13 gr of H4227; It is consistently around 1.2 inches with an occasional .88" group. My rifle barrel seems to like the 150 gr weight projectiles.

  My Marlin .41 1894Fg ( 12 grooves) shoots Jacketed well, and so far has not found a cast round that shoots under 3.5 inches at 50 yards. My Redhawk out-shoots the Marlin by Measured inches, and that is my frustration with cast and MG.
                Vance

[ScatterGunner]

size your bullets as little as possible with the MG barrels. heat treated wheel weights, frequently fluxed with marvelux or bees wax, and alox lube shot good for me, for target only though.

sizing seems to affect the group size more than anything else (as long as the barrel was clean), when you size a bullet, you soften the surface by the nature of the sizing operation. when you size a bullet, it undergoes 2 swaging processes, one when you size the bulet, and next when the bullet is driven into the barrel.

also sort your bullets by wieght using a "bell curve" throw out the light ones and the heavy ones.

sg