Micro Groove rifling

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Lefty posted this 29 February 2012

I recently acquired not 1 but 2 nice Marlin 30-30s. I would like to develop a suitable hunting load. There is much information available about shooting cast in a Micro Groove barrel but as always in our sport, there is no real concensus of opinion. What I have gleaned from the literature is that you want to use a bullet with a long bearing surface, cast the bullet from a relatively hard alloy and size it large for the caliber. One author defined hard alloy as BHN 12 or greater. This seems a little soft but what do I know? The same gentleman also specified .310 or .311 as a reasonable diameter to try first. Yup makes sense to me but see above as to how much I actually know.:thinking: I would love to hear from some of you who are successfully hunting with a micro groove rifle.

One related question I have is regarding linotype. I am fortunate to have a large supply of the stuff. Obviously it would make excellent bullets however I am concerned about the reports that it can shatter upon impact and thus is not suitable for hunting. Is this true at a practical level? If so can the alloy be strengthened with the addition of 2-3% tin? Other thoughts?

Based on what I have read so far, heat treated bullets with annealed noses look like a practical solution. ???

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Brodie posted this 29 February 2012

Lefty;  As to Alloy Ranch Dog recommends water quenched WW 's sized .310 or so (every gun is different) .  The water quenching or tempering of the  alloy doesn't seem to keep it from expanding decently.  Linotype is rather brittle and doesn't expand worth a darn in my experience, and tends to shatter when it strikes something hard like a large bone (shoulder, leg, hip etc.).  My own experience has only been with water dropped WW's in 44 and 41 mag.  Both penetrate extremely well despite striking large bones and have not been seen to shatter.  Lyman no 2 is about the hardest alloy I have ever heard of for hunting, and too hard in my opinion.  When I test fired bullets made of Lyman #2 into packed news papers and magazines I found little to no expansion or deformation of the bullets. Brodie

B.E.Brickey

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Lefty posted this 29 February 2012

Thanks Brodie.

I didn't mention it in my first post but I am also thinking a slower powder, hopefully with a flatter pressure curve might help. Something like 32gr of 4831 or 30gr of 4350 perhaps.

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Tom Acheson posted this 29 February 2012

Lefty,

I've shot (2) Whitetail and (21) Mule Deer, all with an iron-sighted revolver The guns were either a S&W .41 Mag., using a SKS 296-gr. bullet (1250 fps) or my own wildcat (built on a DW .357 Super Mag frame with a Douglas barrel, shortened 220 Swift case, similar to a 414 Super Mag) .41 Wyoming, using a Hoch 323-grain bullet (1100 fps). All bullets have been 100% wheel-weight, have large dia. meplats and most have been “heat treated” in an oven and water quenched. NONE of the wounds I've looked at have had evidence of shattering (most hits through the rib cage). Oddly, it seems as if the entrance and exit wound openings are consistently the same size.

FWIW

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onondaga posted this 29 February 2012

Linotype is excellent to use alloying. I collect scrap at my club berm and ingots measure 7.4 BHN with my Lee hardness test kit. The alloy I mix is a Lyman #2 clone at 7 parts range scrap and 3 parts Linotype. My air cooled and not water dropped bullets test between BHN 14 and BHN 15 after one month.

Adding tin to Linotype will only make it even harder, it already has plenty, don't waste your money.

Your money would be better spent on a lead hardness tester.

There is no mystery getting Micro-Groove barrels to shoot lead well. Use the largest diameter bullet that will fit your chamber throat and still allow your action to operate. Most Marlins will like a .310 -.312 bullet and you will end up selecting a bullet size likely .003” larger than your bore slugs out at from Groove to groove.

Success also involves a Lyman “M” die to expand the case neck and flare the case mouth before seating bullets, although some do fine using the Lee universal case mouth flare die. Do not make the mistake of avoiding that step before seating bullets. Your nicely oversize bullets will be sized down by your brass if you do and you will have the problems that shooters complain about with Micro-Groove barrels. I am talking about leading, bullets tumbling in flight, and poor accuracy.

The RanchDog bullets will get you accurate the quickest. They are designed for Marlin lever-guns. Although I have been casting since 1957, I only tried my first 6 cavity molds in the last year. There is a learning curve to learning with 6 cavity molds. If you go that route, read up and study on using  a 6 cavity mold. The molds have to be very well warmed before use and casting cadence very brisk to get them working well. If not, you will break the sprue cutter and get horrible bullets.

Ladle pour into 6 cavity molds can be done but you need a seriously big ladle that will hold at least twice as much alloy as needed for 6 bullets.  You must pour all 6 without stopping and have excess puddle connecting the sprues atop the sprue plate. A bottom pour melting pot is really better for this.

Lyman #2 alloy has been the first choice for cast hunting bullets for over 100 years for a very good reason. Upon hitting game animals with at least 1000 foot pounds energy, the alloy can be depended upon to expand to double in caliber and retain 100% bullet weight. Run a ballistic chart on your load and you will know the maximum range that the 1000 foot pounds of energy is delivered by your load. This will tell you the maximum effective range for a humane harvest of a big game animal in America with a vital area hit using your #2 alloy bullet from your 30-30.

Gary

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Brodie posted this 01 March 2012

Lefty wrote: Thanks Brodie.

I didn't mention it in my first post but I am also thinking a slower powder, hopefully with a flatter pressure curve might help. Something like 32gr of 4831 or 30gr of 4350 perhaps.Lefty;  you might have better luck with Imr3031, 4895, RL7.  I think that 4350 and 4831 are a little too slow for the 3030.  It used to be (back about 1972) that 3031 was considered as too slow for cast bullets in the 3030, and that has been proven wrong so give it a whirl , but I think your velocities will be a little low.  Brodie

B.E.Brickey

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Brodie posted this 01 March 2012

Lefty wrote: Thanks Brodie.

I didn't mention it in my first post but I am also thinking a slower powder, hopefully with a flatter pressure curve might help. Something like 32gr of 4831 or 30gr of 4350 perhaps.Lefty;  you might have better luck with Imr3031, 4895, RL7.  I think that 4350 and 4831 are a little too slow for the 3030.  It used to be (back about 1972) that 3031 was considered as too slow for cast bullets in the 3030, and that has been proven wrong so give it a whirl , but I think your velocities will be a little low.  Brodie

B.E.Brickey

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giorgio de galleani posted this 01 March 2012

The old microgroove Marlin,the one with no safety button,liked311 bullets.

The  recently acqured new stainless with Ballard rifling accepts bullets sized 310.

You better read on theese  facts of  the loaded cartridge's neck clearace in the chamber in EdHarris article in the FS N°190 nov 2007.

I insist for safety reason. 

I use the first Ranchdog mould,and have troated up the gun with a Clymer neck reamer,just to accept rounds seated with the gas check in the neck.

I use a top load of Vihtavuori N°135 at 2200 fps.Decent accuracy,I am refining it.

I would like to work with a heavier bullet,the old BOWM around 200 grs.

Seven months to the boar season,I have plenty of time.

30-30 cartridges ,I used to shoot in a Rolling Block by Pedersoli and in the microgroove Marlin I once had.

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shastaboat posted this 01 March 2012

In my Marlin Micro Grooved Model 336 I have been shooting Lyman 31141 gas check bullet cast in wheelweight at 176.5 gr. I then freeze the bulk bullets for 48 hours and let them age harden for at least 2 months. Sized .310. I use 20 gr of 2400 with .5 gr. of Kapoc as a powder holder and lightly tamp it over the powder. This load shoots into 1.5” avg for me at 100 yards and chronographs at 1995 fps. The ES was 54 fps. You can eliminate the Kapoc but I think it enhances accuracy and consistancy for me. It also seems to scrub the barrel at each shot. I use my homemade 50% beeswax 50% high speed lithium based wheelbearing grease lube for all my cast bullet shooting. No leading observed once the barrel is seasoned.

Because I said so!

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Lefty posted this 01 March 2012

Hey, good stuff. Thank you one and all.

Let me offer a couple of thoughts. First as to powder. I am a fast powder guy generally. I am very intrigued by Shastaboats use of 2400. My thoughts about slow powders, specifically 4831 and 4350 come from some very reliable sources. For years, the Lyman cast bullet manual listed 32-34 gr of 4831 as one of its recommended loads - for heavy bullets. In rereading Ed Harris's thoughts on the 30-30, I found that he used 30 gr of 4350. I will eventually experiment with powder and try both fast and slow.

Giorgio's admonition to be careful about leaving adequate neck clearance is correct I believe. I have noted writings from a couple of sources that professed to turning the case necks “cautiously” to create another thousandth of clearance to accommodate a larger bullet. I hope to avoid that step but duly noted Giorgio.

To finish that thougt, I do not have a source for the proper 30-30 chamber specs. I realize that Marlin may have been generous in its chamber necks but the actual industry specs would be interesting.

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Lefty posted this 01 March 2012

one other thought - a post above mentioned that a tight case neck could actually swage your bullet by a couple of thousandths - my words not his. I am embarrassed that I have never thought of this. I am going to test this effect with a 30-30 case and a fairly hard .312 bullet this weekend.

Again thank you for the well thought out responses.

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onondaga posted this 02 March 2012

Lefty:

The 2 theories on powder for cast bullets are pretty far apart. Both of them work in reason. Fast powders slam the bullet hard with pressure and extrude the alloy to seal the bore---Yes unless you over do it for the alloy strength. Slow powders give the bullet a softer start  to deform them less but rely on a tight bullet fit to the bore.

I  subscribe to the slower powder and  soft start because higher velocities can be reached without going overboard with high pressure.  The fast powders nearly always leave a large airspace in the cartridge.

I do use a fast powder and filler in S&W .500 rifle rounds but still hope to find the right powder that will fill the case and send my 350 grain bullet 1700 fps. . I know it has to be faster than 5744. The powders around that burn rate get tricky in the .500. I can fill the case with that but don't get the velocity. Fortunately the combination I use shoots 1MOA at 50 yards, so I will bear with the filler!

Regarding bullets being swaged by brass. The softer the alloy the more this effect will be found. This is a reason RanchDog recommends hardening his nicely oversize bullets for the 30-30.

I prefer #2 alloy and case neck expanding to fit the oversize cast bullets and have tested them by using a kinetic bullet puller and measuring. It is working for me, my alloy and my brass. Your results may vary, checking pulled bullets is a great way to find out for sure before shooting and having no idea why bullets are flying all over the place.

 Soft alloys and a tight fit in the neck will swage the bullets. Sometimes a fast powder can punch them back up but I prefer not to depend on that.

Gary

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shastaboat posted this 02 March 2012

I actually started using 2400 after reviewing the 1973 LYMAN CAST BULLET HANDBOOK. The 30-30 section did not list it but was a load under 30 Cal Remington. It listed bullet 311291 but I substituted 31141 and that appears to be the bullet pictured. It also gives loads for 4227 and 4198.

Because I said so!

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giorgio de galleani posted this 02 March 2012

I think that the various progressivity of propellants are to be married to the weight of the bullets and the goals of the load.

Light bullets and fast powder for argets or plinking and heavy missiles for deer or boars.

 

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Brodie posted this 03 March 2012

I'm with you 100% Giorgio. I learned a long time ago that fast light bullets on game were just an invitation for trouble. Brodie

B.E.Brickey

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Lefty posted this 03 March 2012

I mikes the neck of a factory round last night. It measured .329-federal cases. I then loaded a .3105 diameter cast bullet into one of the once fired cases. I took care to not swage the bullet as I inserted it into the case neck. As expected the neck of the loaded round miked .332. The loaded case chambered easily in both of the Marlins. I need to fire a few while keeping the micrometer close at hand. I suspect some where between .311 and .312 will be as large as I want to go. A bathroom remodel will keep me from getting to the range this weekend.

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Lefty posted this 04 March 2012

I apologize for jumping around a bit but I am addressing issues as opportunity presents itself. Last summer I settled on an alloy of 1 WW to 1 Lino for my match shooting. I never tested the hardness as it shot well at 1700 fps and that was all I cared about at that time. I tested several bullets in three different styles today. The bullets cast last fall registered 8.1 on the Saeco scale. Those cast 3 weeks ago registered 7.9. These would equate to 12.5 BHN to 13.5 BHN. I would think this alloy will be hard enough to use with Micro Groove rifling if my bullet is large enough. Time will tell when I get some time to go to the range.

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oscarflytyer posted this 07 June 2016

Google LASC and Glenn Fryxell. He hunts with cast bullets in the 12-13 BHN range - very effectively. I have Marlins in 30-30, 35 Rem, and 45-70. Found that sizing them .002 over the norm (.310/.360/.460) works well. I have taken on deer - w/ the 45-70 - 85 yds. Flipped the deer and not recovered. All of these are GCs.

OTH, as mentioned, Mike (Ranch Dog) is WQ his. All are also GCs. And if you look at his load data, he is pushing them. Basically near real hard cast at jacketed velocity. And very successful.

For 30-30 - RL7/H335/BLC-2/IMR 4895/IMR 3031. for 35 Rem - IMR 4064/H335/Varget. 45-70 - IMR 3031. Going to work up a Varget load also. All Trapdoor loads

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BudHyett posted this 07 June 2016

I have tried this and have some distinct prejudices.<>Reloder #7 powder<>It is not position sensitive<>Load for approximately 1800 feet per second <>SAECO #315 bullet<>Wheel-weight alloy<>Big flat nose for tubular magazine<>Sized .311 for the particular rifle<>Try dummy rounds to assure working through the actionThis load combination worked well for a friend's daughter shooting from a stand under one hundred yards. He and I experimented for her to have practice loads approximating factory; she liked the load and went hunting with it. He thought she was using the factory ammo he had bought her until they skinned the deer.

Farm boy from Western Illinois, living in the Magical Pacific Northwest

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oscarflytyer posted this 07 June 2016

Have to agree with a strengthening prejudice for RL #7.

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