Cast Boolit Info Clarification

[fishnbob]

In the 45th edition of the Lyman Reloading Handbook, in the notes under 35 Remington, it reads, "With cast bullets, the bullet should be sized to the exact groove diameter. If the rifle has multi or shallow groove rifling, then cast bullet velocities must be held to 1600 fps or less, if accuracy is to be obtained."
I assume that the micro-groove Marlin falls under the above statement. Do you find this to be true in all cases? The reason I ask is that I am trying to find some reasonable accuracy with my 336 and about the only thing I haven't tried is sizing smaller(357"). Right now I am sizing .358". My gun slugged @.357". The chamber end was tighter than the middle of the barrel, which is where I'm sure the .357" dimension came from. I am sure the middle of the barrel is .358 or .359 maybe. I am using gas checks and when I shot yesterday, the 35 gr loads of #3031(2144fps) shot closer than the 25 gr of 3031(1550fps). In this case, the Lyman info is suspect. Any comments would be appreciated.:cbpour:

[KYCaster]

My Micro Groove 336 likes the RCBS 35-200-FP sized at .358 with 34.5 gr. of 3031.

That load gives me 2090 fps and consistent 2.5" groups at 100 yds. I've found other boolits that are a bit more accurate, but this one performs exactly like Rem and Win 200 JSP's on deer.

Jerry

[gasboffer]

I had a Marlin 336. Slugged the barrel and found tight spots where the sight dovetailed, where the front sight dovetailed, and where the front band fastened to the stock. Went to a softer boolet and groups improved. I assumed the bullet was being squeezed at the tight spots and expanding when it passed them.

[longbow]

I am with the bigger is better crowd. I usually size or shoot as cast at 0.001" to 0.002" over groove diameter.

My recent experiences with microgroove are limited .44 mag Marlin and I generally load to "J" bullet velocities though in my case, most of those are probably at or not much above Lyman's suggestion. However, my opinion is that with a gas check boolit, higher velocities should not be a problem.

Also, as per your comment and gasboffer's about tight spots, my Marlin had several tight spots and was a problem with leading so I hand lapped all the tight spots out (3 or 4) and the gun shoots much better with no leading now.

Longbow

[mpmarty]

I sent my first Marlin 1895 back to Marlin as the bore was constricted under the roll stamping of the legaleze warnings half way down the tube. Marlin was good to me and installed a four groove barrel and returned it to me with a nice letter.

[Buckshot]

...............I'm afraid that if your barrel is larger in the middle and then tapers back down, you're pretty limited in what you can expect accuracy wise. With black powder the ONLY place upset, or boolit expansion takes place is right there where it sits when ignition takes place, and nowhere else. That was proven close to 150 years ago. Smokless IS different and does operate at higher pressures then BP, but I would tend to believe the same thing happens. My only example would be in a revolver where a boolit is fired and passes through a cylinder throat smaller then the grooves in the barrel. usually poor accuracy and leading occur in, and just beyond the forcing cone.

...............Buckshot

[stubshaft]

I've usually found constrictions in Marlins at the barrel band. A few strokes with a lead lap and compound and they were gone. Like Buckshot said you probably won't get the best accuracy out of that barrel. No matter what you size to if the chamber end is tighter than the middle of the barrel it will swage the boolit down. Only lapping the restriction out will help.

[DLCTEX]

I totally disagree with Lyman's statement on size and velocity limits.

[sqlbullet]

I totally disagree with Lyman's statement on size and velocity limits.

As I recall my readings in the Lyman Cast Bullet Handbooks, I think even Lyman disagree's with Lyman's statements.

[williamwaco]

Don't know abut the .35 Remington but I know from personal experience that all that Micro Groove stuff is simply not true. It may happen occasionally but I have owned three marlin Microgroove rifles. All were as accurate as any other type - no more , no less.

My favorite was a Model 336, .30-30 thaa shot 3" at 100 yards with a reciever sight and the Lyman 311041 at 2100 fps.


I expect most of the Marlin owners who couldn't get any accuracy from Marlin MG rifles tried one load. It didn't shoot and they said "Oh well, so much for that. Everyone knows they will not shoot cast bullets."



The Marlins I have owned over the years have shot cast bullets exactly as good as any other brand of rifle.

.

[Canuck Bob]

Some folks prefer the MG barrel. More edges to control the bullet as it accelerates and less deformation due to the effect of the shallow rifling.

[mpmarty]

I don't prefer it but live with it as that's what my 45/70s have and they shoot just dandy.

[Char-Gar]

In this case, Lyman is full of it.

[geargnasher]

+1 Char-Gar and DLCTX.

Keep in mind the statements in the Lyman books about sizing to groove and keeping loads for MG barrels under 1600 fps are made by the same editors that recommend Borate flux and straight linotype, and somehow think you can make Lyman #2 with wheel weights being the only source of antimony.

Gear

[fishnbob]

It's beginning to look like I need a new barrel if I am ever going to get it to shoot consistently. My groups with jacketed bullets suck in my book. 4 to 5 inches @ 100. This has been very frustrating.

[BAGTIC]

I believe in using the largest bullet that will chamber reliably.

Given that recent Marlins are reputed to have oversize .432 bores you will need all the help you can get to fill them.

[Mohillbilly]

I'd say either fire lap , or send to Marlin. AND that would depend on whether it would be a warrenty thing. If you would be out of warrenty for a barrel , I would hand or fire lapp it before spending money for shipping and the new barrel . Do the cheapest fix first or find a trade less than the cost of a new barrel that may or maynot improve the rifle .

[44man]

Long, long ago I bought a Marlin .35---I can't count good enough to tell the year. [smilie=l: I also had trouble with cast and the Lyman stuff even though the gun shot honest 1/2" groups at 100 with a scope and factory loads.
I am almost sure my boolit was a RN, not like the Lyman shown now. It had the same number though.
I wish I still had it with what we now know about cast.