45-70 cast and microgroove

[brnomauser]

Out of interest, has anyone cast and sized bullets big enough in a microgroove marlin 45-70- like .460 or above- and not had success with accuracy and lack of bad leading?

[brnomauser]

can no one confirm either way?

[Bob Krack]

can no one confirm either way?

I'm not certain that eleven hours is enough time to expect an answer.....

:veryconfu

I would bet that several have and with mostly good results. Ya might check with Ranch Dog or Marlin Junky.

Bob

[WHITETAIL]

brnomauser, Welcome to the forum.
I can not answer this one.
but I do load for the 45-70.:cbpour:
And from what has been said in the past
you will have to just a little adjusting with the loads.

[crabo]

460 works well in the one MG I loaded for.

[brnomauser]

thanks guys. Sorry didn't mean to be pushy just feeling a bit rushed... I'm just wondering whether you can always make a microgroove shoot cast well so long as your oversize

[stubshaft]

I have gotten great results with the RCBS 405 and the RD 425 both sized to .460" in BOTH Ballard and MG rifling in all 5 of my 45/70's. Truth be told I didn't get much worse accuracy in the MG rifling when sized to .459 either, but had a .460" Lee type sizer die made just for peace of mind.

[stubshaft]

BTW - None of the boolits had any leading using thinned Xlox for the RD's and Felix for the RCBS even when driven by 53.0grs. of 3031.

[longbow]

I used to have a Marlin 1895 .45-70 with mircrogroove rifling many years ago and shot mostly Lyman 457124 385 gr. RN in it.

Back then I didn't know one should slug and size to suit the groove diameter. I just cast, lubed and shot unsized boolits.

I have to guess that either I had a tight barrel or a mould that cast to the right size because I never got leading and accuracy was good.

It is a PB mould and I pushed to the limits of Hornady's Marlin load recommendations but never had a problem with leading or poor accuracy.

So, I can't tell you what groove diameter or boolit fit I had, just that it worked very well. SO it is certainly doable.

Longbow

[Maven]

brnomauser, The target below was fired from a Marlin #336 Microgroove bbl:

[jlchucker]

I used to have a Marlin 1895 .45-70 with mircrogroove rifling many years ago and shot mostly Lyman 457124 385 gr. RN in it.

Back then I didn't know one should slug and size to suit the groove diameter. I just cast, lubed and shot unsized boolits.

I have to guess that either I had a tight barrel or a mould that cast to the right size because I never got leading and accuracy was good.

It is a PB mould and I pushed to the limits of Hornady's Marlin load recommendations but never had a problem with leading or poor accuracy.

So, I can't tell you what groove diameter or boolit fit I had, just that it worked very well. SO it is certainly doable.

Longbow

I had the same experiencel Longbow. I bought my one and only 45-70 (a Microgroove Marlin 1895 in the early 1980''s. I was already casting for my 30-30, so I looked in a lyman book, saw that the "most useful" sizer was supposed to be .458, and then bought one. It's still the only sizer I have for this caliber, and I've not had any leading, but the rifle shoots most cast boolits as well as I can hold it. I've cast both PB and GC boolits (Lee, Lyman, and RCBS) and they've all performed well. I must have got lucky with a tight barrel. I didn't know much at all about casting when I started. I must have had some really dumb luck. Today I'd slug my barrel first on any gun that I hadn't cast for.

[Marlin Junky]

Gas checked boolits all respond nicely when shot under reasonable conditions of pressure, boolit hardness and velocity. IMHO, the only restriction to accuracy is the tubular magazine and two piece stock of the lever action design itself. Plain base boolits are a bit more challenging.

There's some bum information floating around about current "Ballard Rifling" vs. MicroGroove rifling. Facts are, there isn't .0005" difference in depth between the two and the old 12 groove MicroGroove is probably superior to the current "Ballard Rifling" because there are twice as many lands providing more surface area for boolit engagement. Actually, I've heard of 444 MicroGroove examples having bore diameters as small as .424" while my current "Ballard Rifled" example averages about .425" and is closer to .426" near the chamber. I haven't personally seen any big bore examples with more than 12 grooves (they would be in 444 'cause the 45-70 wasn't offered until '72); however, Marlin didn't convert to 12 groove rifling until 1968 and the 444 came out in '64-'65. Before '68 and back to about '55, Marlin's MicroGoove configuration incorporated 16 and even 22 grooves in their .30, .32 and .35 caliber offerings.

MJ

P.S. Fact of the matter is: no modern Marlin will ever shoot cast like they did prior to '55... and I mean with an alloy that will expand out to 200+ yards.

[longbow]

I sold my Marlin to a friend to help finance my way through college (along with lots of other toys I still miss too!). He is now selling it and I am thinking of buying it back. It has hardly been used since I sold it to him and looks like new.

You are right about dumb luck. I also had a Siamese Mauser converted to .45-70 and had a 26" barrel put on it. I shot the same loads (max for Marlin) through it and where I got no leading in the Marlin (22" barrel) I got leading in the last 2" or so of the 26" barrel. I just figured the extra barrel time and heat on boolit base was the cause so dropped a .410 fiber wad on top of the powder. No more leading, no pressure signs. No chamber ringing.

I wouldn't do that today either ~ not without working up the load anyway. Dumb luck indeed!

I found both those guns very easy to load for.

Oh, same guy bought the Mauser too and it is for sale as well. I would like both but have limited toy budget. I sold them to put myself through college, now I am putting my kids through college!

Longbow

[brnomauser]

Ok well sounds mostly promising. So it is a safe assumption i can get a MG to shoot PB bullets so long as they are cast/sized big enough with reasonable accuracy?

Are GC bullets more forgiving of size or do MG barrels just like them more?

[Maven]

brnomauser, I don't think an undersize, but gas checked, CB will be more accurate than a properly sized one in a MG bbl. Both plain base and gas checked CB's can be highly accurate if they fit the bore. In short, I don't think the type of rifling makes a difference. The gas checked ones, of course, can be pushed much faster than plain based ones; i.e., fast enough to hurt your shoulder in the light Marlin. Btw, the target I posted was fired with a plain based LBT 460gr. CB sized to .459" and seated to 2.55" OAL. I ordered the mould with 1 gas checked and 1 plain based cavity, but soon discovered the recoil with the faster gas checked ones was intolerable and had Veral Smith remove the gas check shank from that cavity.