New to me Marlin 1895 SS 45-70 Microgroove want to shoot cast

[colt45long]

Hi new to forum. I just got a Marlin 1895 SS 45-70 with Microgroove barrel and want to shoot cast. People in the Marlin forum refer to this forum a lot so here I am. I slugged the barrel and have readings .459" to .460" I would like to get a mold that would work. I see NOE has 460-350-RF 2 cavity GC (RD) and curious what size this will drop using wheel weights and I would quench in water to get harder. Some mold drop +.002" over and can be sized. I figure ideally would want a .461 to .462 I also hear I may run into chambering issues running boolits over .4595"
I am guessing but keeping fingers crossed if the .460 mold would work well ?
This has a GC and hope that would help on the leading but would it help on accuracy ?
I have not shot the gun yet. Would like a mold and cast bullets great for plinking and be able to load them hotter for hunting
Please share an advise

[Edward]

Just got mine and it is a 4 cavity ,2 PB and 2 gas checked and they are dropping 460 and is the nicest mold I have used. My reject rate is less than I am accustomed too and I am making way more bullets !

[seaboltm]

I doubt .460 will work with your slugging data. Microgroove can shoot cast, despite what some say, but the boolits tend to need to be larger, say .461-.462, as you noted. If they wont chamber, you can likely have that issue fixed by a decent smith for a nominal fee.

[44man]

They sure will shoot cast if they fit. The Ballard rifling is no deeper then micro groove of .003" so I would prefer micro groove. Ballard for cast was a sales pitch.

[MBTcustom]

The bullet you are considering is the cats meow in my opinion.
If I were you, I would send me a PM, and let me slide you some samples via USPS.
I recomend cast in them from COWW + 2% tin air cooled.
Lube them with a 50/50 olive oil/beeswax lube and use a Hornady gas check.
If that doesn't work, then it's likely the bullet isn't quite big enough to seal the MG rifling, and in that case, powder coat them and size a touch larger (I'll send some of these as well).

Some good loads to consider:
All with Starline brass.
15gr of Unique (1300ish FPS (never chronographed it) with Dacron.
24 gr Aliant 2400 (1520FPS with Dacron)
30 grains of IMR4227 (1530FPS without Dacron, 1635 with Dacron) (disclaimer: some people do not recomend using this powder in the 45-70)
I have heard that Re-7 gives excellent results in the 1800fps range (PM Bjornb on this forum)
Other higher velocity considerations are
IMR 3031
IMR 4198

I highly recommend loads in the 1500ish FPS range with the RD 350 to knock over anything on this continent, and provide as much fun shooting as a 22lr ever did.

[45coltnut]

I second everything that goodsteel stated.

I too have an NOE 460405 PB mold. My highway likes it allot. Currently I'm shooting the cup point version that weighs in at 385 grains. I too push mine around 1500 fps. My mold is dropping around .4605"-.461" and I then size to .459". Should you want a few to try, shoot me a PM.

[flint45]

Micro groove barrels shoot cast just fine. I have a.45-70 that slugs .458 so I shoot .459-460 works good. my boolet is a old 2 cav. Crammer mold 380 grs. flat nose cas check one big grease groove. Shoots real nice with imr 4198 or sr4759,R-7,xmp5744 or imr 3031.