Cast Bullets in Marlin Micro-Groove Barrel [Archive]

Reloader270

11-15-2012, 01:02 PM

Wally

11-15-2012, 01:10 PM

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

11-15-2012, 01:37 PM

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

felix

11-15-2012, 01:38 PM

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

11-15-2012, 01:44 PM

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

11-15-2012, 01:44 PM

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

11-15-2012, 01:53 PM

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

11-15-2012, 01:58 PM

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

11-15-2012, 01:59 PM

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/Firearms/1894centerfire/1894CSS.asp

For an example. Read the barrel description.
.

Ed_Shot

11-15-2012, 02:03 PM

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

Lucky Joe

11-15-2012, 04:43 PM

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

11-15-2012, 06:15 PM

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

11-15-2012, 08:31 PM

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

11-15-2012, 09:29 PM

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

11-16-2012, 12:58 PM

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

11-16-2012, 01:05 PM

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

11-16-2012, 01:29 PM

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

11-16-2012, 03:14 PM

"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

11-16-2012, 04:47 PM

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

11-16-2012, 06:28 PM

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.

Marlin Junky

11-16-2012, 06:58 PM

Good advice here and without reading Glenn's article, I need to add that a good lube and "clean burning" powder go a long way with respect to extracting the best performance from new (post 1955) Marlins. Always take your chronograph and barrel cleaning equipment with you while developing loads and you'll probably find the best loads deliver the smallest extreme spreads in velocity. Also, when shooting these "tougher than normal boolits", you may loose accuracy when exceeding groove diameter by more than a .001-.002" with certain loads (especially loads with a steeper pressure curve). Use the slowest, cleanest burning powders that are reasonable for your platforms and normally water dropped wheel weighs with a little softer lead added with get you the right alloy after about a week of aging. Casting techniques are also important. I like to cast from a hot mold with about 700F metal and open the mold to drop the boolits in water ASAP... this means you'd better have a well lubed mold or you'll have alloy smears everywhere.

MJ

P.S. I just read Glen's article and he neglects to mention that while Marlin has indeed changed the configuration of the rifling on several of their guns since about '98-'99, (oh yes, and now there are barrels marked "REP") the change to the rifling is basically in the width and number of grooves. The grooves are still very shallow and in many cases barely .0025" deep at the muzzle. I have seen pistol cartridge barrels lately that are stamped with REP (Remington's stamp) that appear to have a bit better groove definition but I haven't had a chance to give one a work out yet. I have done a couple of action jobs to the new "Remlins" and they are ROUGH! Hopefully that's no indication of their barrel quality. I mean, it looks like the action parts went to assembly as soon as they left the forge. :bigsmyl2:

Az Rick

11-16-2012, 07:09 PM

I have a 1971 vintage 1894 in .44mag. It shoots cast quite well. The micro grooves like fat bullets. I cast and shoot a Ranch Dog 265grn. bullet that is accurate.

Best, Rick

williamwaco

11-16-2012, 07:26 PM

it looks like the action parts went to assembly as soon as they left the forge. :bigsmyl2:

That is really sad.

I have seen the same thing in several brands of new guns that used to be high quality.

Now that the tools are SO much more accurate than before it doesn't make sense to me.

( I am NOT a 'smith or machinist and can barely use a hammer, so what do I know?)

Marlin Junky

11-16-2012, 07:32 PM

I have a 1971 vintage 1894 in .44mag. It shoots cast quite well. The micro grooves like fat bullets. I cast and shoot a Ranch Dog 265grn. bullet that is accurate.

Best, Rick

With all due respect, saying the micro grooves like fat boolits (or bullets) is simplistic and misleading because casters will think they need a mold that casts way over groove diameter. The real issue is that Marlin groove diameters are typically oversized. For example .3095" in the grooves for 30-30's and approx. .431" in the grooves for the 444. I have a 44 mold that casts .434" boolits which I made especially for my Outfitter (444 of 1999 vintage) and typically, the best overall performing boolit diameter is .432". My Outfitter "mikes" .4305" in the grooves at the muzzle and will chamber a .434" boolit; however, using the harder, tougher alloys needed for "thin" rifling would skew the pressure curve toward the origin (to the left) while shooting such an oversized boolit. I have had good luck sizing at .433" but only with very slow powders; e.g., AA2520, using softer (as soft as BHN 14!) alloy with my near one inch long 345 grain boolits in the .444. It's not really a matter of needing "fat" or "oversized" boolits, simply ones that fit and are usually a bit harder or tougher than normal.

MJ

P.S. BTW, that 345 grain boolit mentioned above has extra wide driving bands to counteract skidding. For example, the leading band is approx. 1/8" long after sizing from as-cast to .432" with a Lee PT.

Marlin Junky

11-16-2012, 07:41 PM

That is really sad.

I have seen the same thing in several brands of new guns that used to be high quality.

Now that the tools are SO much more accurate than before it doesn't make sense to me.

( I am NOT a 'smith or machinist and can barely use a hammer, so what do I know?)

I don't think it matters a whole lot how accurate the CNC mills and lathes are when the cutting tools are as dull as a butter knife and the cutting rates are stepped up to compete with the Chinese.

MJ

geargnasher

11-16-2012, 10:29 PM

With all due respect, saying the micro grooves like fat boolits (or bullets) is simplistic and misleading because casters will think they need a mold that casts way over groove diameter. The real issue is that Marlin groove diameters are typically oversized. For example .3095" in the grooves for 30-30's and approx. .431" in the grooves for the 444. I have a 44 mold that casts .434" boolits which I made especially for my Outfitter (444 of 1999 vintage) and typically, the best overall performing boolit diameter is .432". My Outfitter "mikes" .4305" in the grooves at the muzzle and will chamber a .434" boolit; however, using the harder, tougher alloys needed for "thin" rifling would skew the pressure curve toward the origin (to the left) while shooting such an oversized boolit. I have had good luck sizing at .433" but only with very slow powders; e.g., AA2520, using softer (as soft as BHN 14!) alloy with my near one inch long 345 grain boolits in the .444. It's not really a matter of needing "fat" or "oversized" boolits, simply ones that fit and are usually a bit harder or tougher than normal.

MJ

P.S. BTW, that 345 grain boolit mentioned above has extra wide driving bands to counteract skidding. For example, the leading band is approx. 1/8" long after sizing from as-cast to .432" with a Lee PT.

You gots it.

Like Beagle, said, the largest boolit that will chamber often works best.

If you don't get all, I mean ALL the copper fouling out, they won't shoot cast for beans. Reason is the oversized groove dimension allows a LOT of blowby with copper jacketed bullets and that fouling really gets laid down in the first few inches of the barrel. This makes a restriction that causes gas leaks further up the barrel with cast, and that causes leading and inaccuracy.

Also, if a Marlin levergun won't shoot, make sure it won't shoot with JACKETED either, because a lot of them have warped forends and such that put the barrel in a heck of a bind and string groups every which way as barrel temperature changes. Don't automatically blame the rifling design.

BTW, my 1966, 12-groove 336 in .30-30 will put five Ranch Dog 165-grainers into 7/16" pretty regularly (starting from a cool barrel) at 100 yards from bags with a 4x scope. I'm not going to post the velocity here because none of you would believe me [smilie=l:.

Gear

Marlin Junky

11-16-2012, 11:52 PM

You gots it.

Like Beagle, said, the largest boolit that will chamber often works best.

With softer alloys, moderate velocities, low sectional density boolits, and slower powders, yes... often. However, when dealing with thin rifling, if one wants to jack up the boolit weight and top out the velocity while maintaining good accuracy... heat treated boolits that are closer to .001-.002" over groove diameter have worked better in my experience. Slowing down the powder (flattening out the pressure curve) will enable accuracy with softer alloys but I believe when alloys are upwards of 25 BHN, boolits diameters shouldn't exceed .002" over groove diameter. I suppose an exception could be made for ridiculously slow powders but I don't substitute gunpowder for filler.

Now with all that said, if one needs a boolit that's .003" over groove in order to fill the throat, I say go for it and see how it shoots. The throat configuration may be such that the fatter boolit works best. In my '06, (with normal rifling) I shoot nothing but .311" boolits because they fill its throat which has a shallow angle into the rifling. The groove diameter is .3085" and it shoots very well... with mild loads. Returning to the Marlins though, very few of them chambered for straight walled cartridges actually have throats.

Anyway, you'll just have to experiment in order to find what works best for you. My Outfitter has been one of my more challenging guns to cast for simply because of the shallow rifling; however, eventually I accumulated a slew of combinations that have worked well for me from .431" to .433", BHN 13/14 to BHN 30. From GreenDot at 1300 fps to H335 at 2200 fps. From 240 grain PB to 345 grain GC... and occasionally, even heavier boolits intended for the 43 Spanish (loaded singly).

MJ

P.S. One other factor that I just thought of is that .0025" tall rifling is a lot "taller" relative to a .30 caliber boolit than it is relative to a 44 caliber boolit... so if you're shooting a .30, you may have more leeway than if you're shooting a big bore.

Slow Elk 45/70

11-17-2012, 03:14 AM

MJ , thanks for your insight , I won't claim to have experienced the same info that you put forth, I can see you are a student of the CB...I do know that with my guns , .002 seems to work for me, and yes I water drop them...contrary to some who suggest this is Loony....:groner:

greyling22

11-17-2012, 11:50 AM

I've never run anything but cast through my early 80's 1894 in 357 with microgroove. It shoots fine for me. I put 10 rounds into a large ragged hole at 20 yds the other day. Actually leads less than my smith 686. I'm using a 125grn lee round nose bullet cast of about 25%ww and 75% lead water quenched. They drop about .360/.361. I load it over 5.5grns of trap 14 for a velocity of 1200fps, give or take. It's very old powder so it tends to burn a little erratically and velocity varies. I tumble lube with LLA.

Marlin Junky

11-17-2012, 01:36 PM

greyling22

11-17-2012, 02:51 PM

nope. but I figure it is oversized because for a while I tried running my 9mm bullets through it (.357/.358) and they didn't shoot very well.

geargnasher

11-17-2012, 03:06 PM

My 30-30 has a .303" bore and .309" groove, or .003"-deep grooves. It has twelve of them. A typical .30-'06 sporter has .300 bore and .308 grooves, or .004" deep, and has four of them. That's a factor of 16 times the bearing length, whereas the Marlin has a factor of 36, more than TWICE the rotational bearing surface.

See how silly it is to stay that the shallow, micro-groove rifling will strip boolits more easily?

If a mechanical engineer is designing a splined shaft for a certain amount of working torque, peak torque, and shock loading (among other factors), and he finds he needs more strength, the first step is to add to the spline count to increase the bearing surface. A 32-spline transmission output shaft can withstand a lot more torque than a 16-spline one, even if the splines on the 16- count shaft are deeper.

Gear

felix

11-17-2012, 04:18 PM

The only time stripping comes about in a 12 land microgroove is using the wrong lube for the condition. Keep the barrel clean any way you know how, and don't let fired lube stay in the barrel over 20 minutes unless you have a lube that doesn't fire age. WE are working on such a lube; see Gear's thread on this universal lube design. ... felix

uscra112

11-17-2012, 05:34 PM

sthwestvictoria

11-17-2012, 05:46 PM

I asked some similar questions and got lots of good replies in this thread:

http://castboolits.gunloads.com/showthread.php?t=169813

About getting my 336w to shoot. Hardness, fat boolits, more energetic powder than trailboss, bore-riding boolits were the main pointers people had.

felix

11-17-2012, 06:20 PM

So, if I shoot undersized boolits through a clean bore they won't strip?

Go back to post #4 this thread. ... felix

KYCaster

11-17-2012, 07:19 PM

Oh, man!!! I'm doin' everything WRONG! :groner:

I have a 1972 vintage 336, 35Rem.

I'm shooting the RCBS 35-200-FP.....too heavy for the velocity.......it'll strip the rifling.

2075 fps.........too fast for the alloy........it'll strip the rifling and lead like crazy.

ACWW.........too soft for the MG rifling.........I need to add some Pixie Dust or something, or at least heat treat it to get it up to a reasonable hardness.....20-22 BHN.

And they're WAY too small.... .358 dia.......it'll strip the rifling, lead like crazy and be wildly inaccurate.

I don't clean the barrel.........how can I expect to hit anything......shots will be all over the paper. I cleaned it good after the last J-word through it and again four years ago after about 300 rounds of load development and accuracy went to pot both times. The last time it took 35 rounds to season the barrel and get it to behave, so it's going to take something drastic to make me clean it again. If it's going to sit in the safe for a while, I'll pull a bore snake through it followed by a patch with Bullshop Speed Green and that's all the cleaning it's had in well over 200 rounds.

I don't HP.....I expect a puny little meplat to do the work.

........

..........

.........

It sure does kill deer though! :violin:

BTW......I also have an old beater 308 on a commercial Mauser action that has 12 shallow grooves in the barrel. It acts a lot like the Marlin, although it does like .311 dia boolits............but then, so does my Win '94, and it don't have no steenking Micro Grooves.......go figger! :veryconfu

So, bottom line..........you gotta figger out what your gun likes.......and it may take a bit of experimentation.

Jerry [smilie=s:

Marlin Junky

11-17-2012, 07:21 PM

See how silly it is to stay that the shallow, micro-groove rifling will strip boolits more easily?

Gear

Well yes and no, Gear. Your 12 groove MicroGroove configuration is probably the best rifling configuration Marlin ever produced with the possible exception of the old 7 groove true Ballard configuration boasting .0045"-.0050" deep grooves that showed up on early 336's in .35 Remington. Unfortunately, Marlin produced several "inferior" MicroGroove configurations to include the modern 6-Groove "Ballard" rifling (from '98-'99 up to at least the point when Marlin was purchased by Remington) and the 16 groove configuration with its .002" deep grooves. Actually, I believe the .219 Zipper only had .001" grooves. There were even some 20 and 22 groove .30 caliber models made in the late '50's to be aware of; however, assuming they had .002" deep grooves, theoretically, one would be better off with those models vs. the 16 groovers.

Yes, measure the internal bearing surface area before you purchase any Marlin. :bigsmyl2:

MJ

geargnasher

11-17-2012, 08:14 PM

I have an early 1955 7-groove in .35 Remington, great shooter. The 16-groove barrels still have a bearing factor of 32, so still nearly double that of a 4-groove, .004"-deep barrel. I'm not buying the stripping thing. Like you said, though, the Marlin bore/groove dimensions on MG barrels are typically oversized a bit, and boolits must be made accordingly.

Gear

uscra112

11-17-2012, 09:07 PM

Go back to post #4 this thread. ... felix

Non commentus est.

felix

11-17-2012, 10:51 PM

Capit vicis intellego! ... felix

Marlin Junky

11-18-2012, 01:17 AM

Gear,

Perhaps you could explain how you're computing your "bearing factor".

In my mind, the surfaces of the lands that oppose rotation would be your "bearing factor". Therefore and for example, a 16 land/groove configuration would have 16 surfaces opposing boolit rotation (only one side of the land opposes rotaion). In the case of .002" tall lands and given barrel cross-section 1" long, that would yield .032 square inches opposing boolit rotation.

Under the same assumption a 4 land/groove configuration with .004" tall lands, would have .016 square inches or 1/2 the "bearing factor". Is this what you're driving at?

MJ