Cast Bullets in Marlin Micro-Groove Barrel

[Reloader270]

I ran into a guy today telling me that the micro groove Marlin Rifles are not good with cast bullets, even with gas check bullets. Is there is trick with the Marlin Micro Groove barrels. Must the bullet be 0.001" larger than the bore diametre or should it rather be the exact size of the bore? He also said that it is not good to shoot cast bullets in higher than 1000fps in a micro groove barrel.

Could you please give me advise on this. I have a Marlin .357 Magnum.

[Wally]

I ran into a guy today telling me that the micro groove Marlin Rifles are not good with cast bullets, even with gas check bullets. Is there is trick with the Marlin Micro Groove barrels. Must the bullet be 0.001" larger than the bore diametre or should it rather be the exact size of the boar. He also said that it is not good to shoot cast bullets in higher than 1000fps in a micro groove barrel.

Could you please give me advise on this. I have a Marlin .357 Magnum.

I have one. Earlier this month I was shooting it at 125~150 yards with cast bullets...the target was a 4" wide steel plate. Using a rest and a 4.5X scope I coudl often hit the plate with a Lee 158 RF and a Lyman 358311 bullets. The 358429 Lyman Keith did not shoot well, nor did a Lee 140 SWC. An RCBS 150 SWC did quite well. None had GC's on them. Average muzzle velocities were 1,400 FPS.

[Reloader270]

Wally thanks for the information. I intend using a 162gr RCBS Semi Wad Cutter with Gas Check with a speed of +-1600fps.

[felix]

It stands to reason that "microgrooves", say less than 0.003 in depth, would require cleaning more often for the same level of accuracy. Speed accomplished would be a function of boolit grip within the barrel, and that be the number of lands. So, make the boolits the maximum size diameter that would be a manual fit within a fully loaded fired case from the gun. As the boolit gets smaller, the hardness of the boolit skin must be greater for the same level of accuracy. ... felix

[Lucky Joe]

Glad this came up I have a Marlin 1895 C and I want to shoot a Saeco 350 gr. boolit in it. Calls for a gas check, been wondering if paper patching would be a good idea, for the micro groove barrel.

[Wally]

Wally thanks for the information. I intend using a 162gr RCBS Semi Wad Cutter with Gas Check with a speed of +-1600fps.

I size mine to .359"...I once tried a Lyman 195 grain RN in the 1894C..it was not accurate nor was the 168 Kieth 358429... I have a Freechex GC maker tool and tried the RCBS 125 RN-GC in the carbine--it worked out very well for me. I would guess that a GC helps keep the barrel very clean.

[Glassman66]

Here is an article I read on the micro groove barrels by Glen Fryxell. I love reading his stories.


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


Randy

[pdawg_shooter]

Glad this came up I have a Marlin 1895 C and I want to shoot a Saeco 350 gr. boolit in it. Calls for a gas check, been wondering if paper patching would be a good idea, for the micro groove barrel.

I have 4 Marlins, 3 with MG barrels. I paper patch for all of them. Jacketed accuracy and velocity. Whats not to like? BTW I think an 1895C would have Ballard style rifling.

[williamwaco]

I have owned two microgrooves back in the '70s.

In my experience EVERYTHING you hear derogatory about Marlin micro groove barrels is false.

( Based of course on only two examples. )

Both were .30-30s. Both shot the exact same load as I used in my Winchester 94.
Both were significantly more accurate than the Winchester.

The load was Lyman 311041 hollow point sized .311, weighed 160 gr, with a stiff load of 3031.

I don't remember the exact charge but it was two grains less then the then listed maximum charge for a 160 grain jacketed bullet. Velocity was around 2000 fps.

Consistently grouped in 3" at 100 yards from either rifle. No leading and only normal cleaning.


I will bet you a Big Mac against french fry that you can get 1600 fps with no trouble and reasonable accuracy if you size .358/.359.


PS. Not all Marlin .357s have microgroove rifling. Have you checked yours?

See:

http://www.marlinfirearms.com/Firear...re/1894CSS.asp


For an example. Read the barrel description.
.

[Ed_Shot]

Mine has shot great with Lyman 358156 w/gc sized .358 over 13.5 gr of 2400 for more than 30 years.

[Lucky Joe]

I have 4 Marlins, 3 with MG barrels. I paper patch for all of them. Jacketed accuracy and velocity. Whats not to like? BTW I think an 1895C would have Ballard style rifling.

My goof up, I meant 1895SS and it is stamped Micro Grove. Thanks for catching this.

[gunseller]

I have a 1895SS with a micro grove barrel. How fast do you want to go? I have gotten a 400 grain plain based cast bullet of ACWW sized .458 to a little over 2000 fps. I was using a lot of IMR 3031. I do not remember group size, I think it was around 2.25 inches at 100 yards. The load sure put deer down out to 150 yards. They went down like they had been hit with a Mac Truck. So when someone tells you that MG rifling will not shoot cast bullets fast you can smile and walk away or ask them how come they shoot .22s well. Usually ends the conversation.
Steve

[gon2shoot]

I have heard the horror stories about the MG barrels, thankfully my guns havent. Like anything else fit is king.
I normally cast a couple thou. over bore, and use a little harder alloy (like 16/18).

[geargnasher]

Here is an article I read on the micro groove barrels by Glen Fryxell. I love reading his stories.


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


Randy

+1, that's a great article by a guy that actually shoots cast in his MG Marlins!

Microgroove barrels are most excellent for cast boolits, at full velocity, provided you load with the right philosophy in mind. I actually prefer them, they present far more rotational bearing surface to the boolit than conventional, .004"deep, 4- or 6-groove rifling. Being button-rifled, they're also very consistent inside.

Gear

[beagle]

Ah, the old micro groove controversy. I have had several micro groove rifles that I played with extensively over the years. One was a .30/30 336 and the second was the .44 Mag.

After expending probably ten thousand rounds through these two rifles, I came to the following conclusions about getting accuracy from the microgrooves.

1. Use the largest diameter bullet that will chamber when loaded.

2. Use a gas check always.

3. Use the hardest/toughest bullet you can find.

With these rules in effect, you'll get fair accuracy from micro groove barrels. I was never able to shoot good groups with either but the hunting/plinking accuracy was there on the .30/30. The .44 never did well for me at all and I attribute that mainly to the slow twist that Marlin put in these rifles.

I know there are those who will dissagree with my results but that's been my experiences with micro groove.

Needless to say, neither of those rifles are in my safe today.

Try micro groove and if it works for you, fine. If not, move on. No sense in beating your head against a wall. It won't help and feels good when you quit. Life's to short to waste on something that don't work for you./beagle

[popper]

For the Marlin .357 Magnum it shouldn't be a problem with the right CB and load. My 22LR is most accurate with lead. My 30-30 is good too.

[Shiloh]

I don't own a microgroove barrel. I have fired them with good accuracy as the above posts attest.
As with any firearm, it takes tweaking. Great article by Glen Fryxell

[Four-Sixty]

"ask them how come they shoot .22s well. Usually ends the conversation.
Steve"

That is a great point. I swear I can hit a dime over and over again at 50 yards with my model 60, a decent scope and some CCI ammo.

Tweak your rifle. That is the joy of being a caster anyway, right?

[mpmarty]

My experience over thirty years of shooting my 1895 45/70 agrees with everything Glen says except the gas checks. I don't need or use them, even on RanchDog 350gr .460s with stout (around 25gr) of 2400 and ACWW cast boolits. Now I just bought a 457122 Lyman mold and will see what a 330gr hollow point will do for accuracy and bambi stopping.

[MT Chambers]

My experience with MG barrels started out poorly, both a .444 and a 30/30 did not like the cast bullets I fed it, the .444 required .432" bullets and I had to stop using the dry moly I had been testing at the time. The 30/30 requires .312" cast bullets and like the .444, needed gas checks, so they work for me but I prefer the Ballard rifling.