Boolits and Microgrove barrels?

[Tactical Lever]

I know it's been done with success, but how tough is it? Considering another gun with microgroove and wondering if it's worth waiting for a newer version to come up? Also taking into consideration that the slightly older JM (70-80's) are considered better built. Opinions on that?

[GooseGestapo]

What caliber?

.30/30, easy to get a mold that throws .311-.312", and size to .311".
It can be more difficult for the .35Rem as most sources don't make a sizer larger than .360". I got lucky as my .35Rem likes .360".

The .44mag is the most problematic. Even .431" might be undersized, and the 1/38" twist is too slow for heavier than ~310gr bullets.

[Mr Peabody]

I guess I'd be more concerned with how much I liked the older one. Either can shoot pretty nice.

[missionary5155]

Good morning
The simple solution is NOE molds. They produce the Ranch Dog molds that were kindly designed by "Ranch Dog" to work in Marlins.
Otherwise... Load the fattest cast your rifle throat will accept. Then start working back to the thinnest diameter that will still shoot accurately. You may discover the fattest was the best as I have with our 45-70, 444 and 41 mag.
Mike in Peru

[OverMax]

So I believe a found to be
No need to resize a rifle bullet if a mold drops the preferred diameter bullet right from the mold.


the slightly older JM (70-80's) are considered better built. Opinions on that? Not really. Just more wear on em.

[17nut]

http://i.imgur.com/X2oMSw1.jpg
http://i.imgur.com/v92Q7oN.jpg

My 44MAG MG has done close to 5k cast shots in the past 8 years and see a boresnake twice a year, whether it needs it or not.

[sghart3578]

I shoot .311" in my 30-30 and .360" in my 357 mag with great results.

[higgins]

Cast an oversize bullet and size accordingly or shoot unsized lubed with liquid alox - cast a hard bullet (I use wheel weight metal or recovered cast bullets) - use a gas check.

[williamwaco]

The first rifle I ever used for cast was a Marlin microgroove 336 in 30-30. This was in the ancient times before the "gods" ( little g) proclaimed it couldn't be done. The bullet was the 31141. Sized 311. The powder charge was 3031 somewhere between starting and max for jacketed. I didn't have a scope but I scrounged up the five bucks for a Williams 5D "peep" sight. This combo produced 2 to 3 inch groups at 100 yards and would hit a number 10 can at 150 9 of 10 times.

My mentor taught me to ignore all advice about slugging the bore and .001 over groove diameter. There is only one rule. If it is 30 Caliber size it 311. That rule has never failed me. I still follow it today.

[Tactical Lever]

What caliber?

.30/30, easy to get a mold that throws .311-.312", and size to .311".
It can be more difficult for the .35Rem as most sources don't make a sizer larger than .360". I got lucky as my .35Rem likes .360".

The .44mag is the most problematic. Even .431" might be undersized, and the 1/38" twist is too slow for heavier than ~310gr bullets.

I have a .35 Remington that I plan on casting for (one day..), and I am looking at picking up a .444 Marlin. It seems that it would be problematic as well. Same twist rate from what I've read.

[richhodg66]

"If it is 30 Caliber size it 311. That rule has never failed me. I still follow it today."

This is me as well. Mostly because I'm lazy, but it seems to work. I only have one rifle so far that seems to like them a bit smaller, but most do as well with .311 as they do with anything and most of them do better than sized to .309.

My oldest son is back home from the Service now and has a Microgroove Marlin I gave him he likes very much. I have the Ranchdog mold and others. We zeroed his for jacketed 170 grainers, and loaded up a lot of them teaching him to reload, so probably won't get to cast in that rifle until that is all shot up. All my other Marlins are pre-Microgroove.

[MOA]

I have a original Marlin model 375, chambered in Win. 375. Have been shooting as cast with a GC. Using RCBS mould that drops at 264 most times. Got the new XLR's in 30/30 & 45/70 when they were offered with ballard rifling which would be best with cast. All my boolits wear GC's. Make'em as fat as you can that will chamber and most of the issues are behind you.

[MyFlatline]

All my Marlins are Micro Groove, 4-30-30's 3-35's, 2-357's, 2-44's 2- 308mx's, 1-375 and 1-444, I don't have any issues with cast.

[sghart3578]

For what it is worth I will add this.

My 1894C (357 mag) is the one gun that goes with me to the range every time. It is my all time favorite to shoot. I load a NOE 360-180 PB, sized to .360" over whatever powder gives me 1300-1400 fps at the muzzle, this time it happened to be True Blue.

On my last range trip I was struggling with a new to me muzzleloader. Now, shooting a muzzleloader is all new to me and to say I was frustrated would be an understatement.

My son was with me and he would act as a spotter. I was hitting 12" groups at 25 yards with my muzzleloader and I was not happy. We had an 8" target painted white at 50 yards. It had a 2 1/2" orange dot in the middle. Just to make sure my shooting technique was not the problem with the muzzleloader I picked up my Marlin and fired 5 shots at 50 yards.

My son looked at the target, dropped the binoculars and said "All five in the orange dot."

Marlin microgroove barrels can shoot cast bullets, no problem.

[beezapilot]

A very nice article to read.......

http://www.lasc.us/FryxellMarlin-MicroGroove.htm


The book referenced in the article is a bit too pricey for my pocket- but ....

https://www.hamiltonbook.com/marlin-firearms-a-history-of-the-guns-and-the-company-that-made-them

[Harry O]

I have an early 1990's Marlin 1894 in 44-40 caliber. I got some CAS loads and tried it out. Leaded up worse than any gun I have ever leaded before or since. It looked like it was smoothbore the first several inches of barrel. I had a few jacketed Winchester cartridges and shot them to try to clear out the leading. Didn't work. It ironed down the lead somewhat (I could see the top of the rifling) and spread it further down the barrel. It took me a LONG time to clean that out.

The next step was to do some measurements. I found the barrel was a 0.430" .44 Magnum barrel. The CAS loads had correctly size bullets for original 44-40's (0.427") and were dead soft. No wonder it leaded. I ended up with a harder bullet sized 0.431" to work correctly. Luckily the chamber of the Marlin was large enough to take a bullet that large. I had to change to a larger neck expanding die to load it. Also, the 44-40 cases came out straight sided, which made for short case life. But it worked, and was accurate.

[JFE]

I have a .35 Remington that I plan on casting for (one day..), and I am looking at picking up a .444 Marlin. It seems that it would be problematic as well. Same twist rate from what I've read.

Even with a 1 in 38" twist a 44 mag will stabilize a 300gr bullet. My best results have been with hard, GC bullets sized to 0.433".

My experience with a 444 is limited but it shot cast really well. Nothing to do with the twist, just be aware that the OAL and short throat of the 444 will limit cast designs that work best.

There are a series of articles written on using cast in a 444 that would be worth a read. The writer was achieving good accuracy with the 1 in 38" twist rifle using bullets weighing well over 300gr.

[JFE]

Here's the first article in the series on the 444 mentioned above:

https://www.beartoothbullets.com/tech_notes/archive_tech_notes.htm/17

[MyFlatline]

Micro groove, 444 and cast...not a problem 199422

[Tactical Lever]

Thanks for all the input, guys!

[Maven]

One more image for you, TL (below). The gun is a Marlin #336 with MG rifling and the CB's are plain based, WW +1% Sn, but not heat treated.

[john.k]

If anyone cares to look in the chart on P6,its easily seen that most of whats talked about Microgroove is drivel..........100 years ago,Marlin barrel grooves were 002-0025 deep,not 006 as claimed by "ex-perts".

[wv109323]

Microgroove barrels are usually larger then nominal size. A custom mold and sizing die may be needed to get the bullet large enough to fit the bore. A bullet plus powder coating may be an option. Once worked out they shoot fine.