.311 diameter CB's in 30 cal microgroove? Thinking...

[catboat]

Just thinking with my keyboard...

part 1:
I haven't done a lot of casting/shooting with my Marlin 30-30 with microgroove barrel. I have Ideal 31141 and 311291 molds, and some bullets I casted 10+ years ago of a non-discript alloy (probably wheel weights), sized at .309.

part 2:
I've read that microgroove barrels shoot better with larger diameter bullets.

thought process...

Anyone ever try the "31 caliber" flatnose bullets for 30 caliber microgroove? I came across the Saeco .311 180 grain gc flat nose, and it made me wonder if it would be beneficial for accuracy in a 30 caliber microgroove. Not sure if it would fit in the throat or not.

Like I said-just thinking with my keyboard. Anyone size bullets destined for 30 cal microgroove at .310, .311, or larger? How did they work (chambering, accuracy?).

I think I have a .310 sizer die someplace in my box-o-stuff on my reloading shelf. Will try eventually.

Here's the bullet (SAECO #305 31 al 180 grain flat nose) that got me thinking (after reading about the SAECO #315 tapered 30 caliber bullet that has a .311 base)....

http://www.midwayusa.com/viewProduct/?productNumber=137367

[RU shooter]

with my rifle a 1971 marlin bigger was definitely better . Boolits sized.312 shot the best for me


Tim

[Maven]

catboat, Marlin Microgroove bbls. are little different than "normal" bbls. with respect to CB's. I.e., bullet fit is of primary importance regardless of rifling type. Also, the "correct" [size to] diameter depends on when your bbl. was manufactured, and really boils down to what slugging YOUR bbl. reveals. E.g., my ca. 1990 Marlin .30-30Win. (Microgroove) shot some .311" CB's well, but those sized to .310" were exceptionally accurate. Btw, the latter included Ly. #311466 and Saeco #315 (FP, tapered, 175 gr. GC design). It did not, however like either #311291 or #311041 (aka 33141).

[runfiverun]

remember that usually a larger bearing surface designed boolit usually also has a larger nose size.
the 312 body sounds great till the 304 nose jams into the rifling.

[Char-Gar]

30 cal Microgroove barrels tend to run a couple of thousands larger in the grooves and lands than nominal 30 caliber spec.

SAECO lists a 180 grain 30 cal GCFN (307) . They call it a 31 caliber and it is their offering for the .303 British round. It is nothing more than a fatter version (body and nose) of their 180 grain FNCG 30-30 bullet (305.

SAECO 307 is not worth much in the .303 Brit round, but is by far the best 30-30 Microgroove bullet around. Sized .312 on the body, I shoot them over 30/3031 for about 2.2K fps with accuracy on par or better than factdory jacketed ammo. I use No. 1 alloy.

For the fellow wanting to buy a mold for a Marlin 30-30 MG, they can't do any better than SAECO 307.

[desteve811]

Cant determine for sure until you slug the barrel. I also own a Marlin 30-30. Barrel slugs at .305 and i size my bullets to .310 with very acceptional accuracy.

[22Scadoo]

I use the Lee C309-150-F sized to .309 im my Microgrove Marlin with 30g of IMR 4320. Not sure the fps but its just as accrurate as factory hunting loads and has the same point of aim, no adjustments needed to my scope.

[largom]

I shoot the Lyman 311041 sized/lubed at .312 in my Marlin 336. Accuracy is very good. You are going to find that every gun has a mind of it's own as to what will shoot good or not. Best way to find out is to load them up and shoot.

Larry

[DLCTEX]

My Marlin 30A shoots the Lee 311- 170 fn (sized 311) very well. It does engrave the boolit nose in the rifling, and sometimes requires a firm squeeze to close the bolt. I have the Lee 309-170 fn mould now, but haven't tried them in the Marlin as yet. R-7 and SR-4759 have given the best accuracy of the few powders I have tried.

[redale1]

Some twenty years ago I tried cast bullets made of wheel weight dropped in water in both a 357 and 44 rifle. Neither rifle would shoot them and after a few rounds the bores were so leaded that I gave up even trying. Sent the guns back to Marlin had standard riled barrels put on both guns. Using the same loads as befor have not had any probles with either rifle since I had the barrels changed. 44 was 200 gr. sized .430 and the 357 was 158 gr sized .359. Both molds were Lymans. They were used with the companion hand guns.

[Char-Gar]

Red... I have a Marlin 357 with the traditional rifling and a 44 Mag with the Microgroove and can tell no difference in how they handle cast bullet. The 44 does have a slow twist and doesn't do normal to heavy weight bullet at lower than full snort Mag velocities.

Over 10/Unique in the 44, the discontinued RCBS 225 GC (sized .432) will shoot under one inch at 50 yards. Use the heavier 429244 and the groups open up to six inches. Put that heavy bullet under 20/2400 and the groups go back to the inch range.