Infamous Bunny Gun Gets New Barrel in 10x25Rmm

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Ed Harris posted this 17 December 2018

I just received back from John Taylor one of my pre-war small frame H&R .410 receivers with its new 10x25Rmm barrel.  John fitted, and turned the 22" Green Mountain 10mm blank, fabricated and installed the underlug, fitted the extractor, bushed the firing pin, chambered the barrel, machined muzzle for M14 front sight, then drill and tapped the barrel for XS ghost ring peep and a Weaver base, on which I currently have an old Weaver El Paso K4 and blued the barrel.  

Gun is 38" overall and weighs 5 lbs., 1 oz. without scope and 5 lbs. 15 ozs. with scope. Plan is to zero both irons and scope at 100 yards, then chronograph some of the loads leftover from testing the Blackhawk featured in the current issue of The Fouling Shot.

I expect that 5 grains of Bullseye with Accurate 40-182H will be close to .38-40 black powder rifle ballistics.  I expect also that the mild loads with 3.5 grains of Bullseye which are about 800 fps in the 5" revolver, will have a mild report, remain subsonic in the rifle, so being relatively quiet, but still hard hitting, fully equal to a .40 S&W or .38-40 revolver.

I now have 182FN, 220FN and 224 grain ogival wadcutters to try in the rifle.  A heavier 250ish grain bullet, optimized for rifle use is underway at Accurate. Drawing to come soon.

Should be just the ticket for bunnies, bucks and varmints in our West Virginia woods.  Stay tuned!

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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frnkeore posted this 18 December 2018

Can you tell us more, about the 10 x 25R cartridge?

Frank

 

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Ed Harris posted this 18 December 2018

Our 10x25mm Revolver project was spawned during a chat over adult beverages between myself, Mike Hastings, and Sam Hotton. Sam in particular is a fancier of fine single-action revolvers...Our fantasy was a modern, RIMMED .40 cal. cartridge, which using either .40 S&W or 10mm jacketed or .38-40 cast bullets. It would serve the medium game “packing pistol” role, approximating .38-40 black powder rifle ballistics with smokeless, from a sturdy revolver, in a smaller, sturdy case, formed from common brass, avoiding the excess free airspace and fragile nature of .38-40 brass. A case full of black powder or Trail Boss would be adequate for Cowboy Action, plinking, or small game at about 700 fps with either round ball or bullet. 

The .44 Russian case...when necked down to .40 has a capacity of 20-21 grains of 3Fg, 4.0-4.5 grains of Trail Boss or 14 grs. of IMR4227, filling the case to the neck-shoulder junction "gently, without compression" using the RCBS Little Dandy Rotor #18. Using the RCBS Little Dandy Rotor #20 a charge of 16 grains of IMR4227 is compressed 1/16" with the 40-252H at 1.50" OAL.

From our custom 5-inch Ruger Blackhawks, smokeless performance with Bullseye powder exceeds .40 S&W factory ballistics. With “magnum” pistol powders it shows promise to produce a powerful hunting load approximating the 10mm Auto. We attained 1000 fps with Accurate 40-182H and 950 fps with 40-220H cast bullets with 5 grains of Bullseye. With 7.4 grains of Auto Comp we got 1140 fps with the 180-gr. and 1080 fps with the 220-grain cast bullets. Indeed an adequate “packing pistol...” 

Dave Manson made our reamer...John Taylor...rebarrelled our Rugers using a Green Mountain “gunsmith special” 10mm barrel with 16” twist, rechambering one cylinder for each gun to .40 S&W, and the other to 10x25mm. .

Source brass...is...Starline .44 Russian, which we neck down and use as-is, resulting in a 0.970-0.975” case. The shoulder angle is 6 degrees, 48 minutes Basic, the same as the .38-40 Winchester.  Case body diameter is .454" at the shoulder, the same as the .38-40 and .457" at the base, and the same as the .44 Special.

“DougGuy” in North Carolina made our loading dies by cutting down and honing out .38-40 Lee dies on his Sunnen hone... Doug’s firm price to modify your set of LEE .38-40 dies to 10x25mmR is $150.  You supply Lee .38-40 dies, Doug does the mod, and returns your dies insured in small flat rate box.  A shortened Lee Quik-Trim case holder, to cut .44 Specials, costs a bit extra. 

The die alteration process is as follows:

1)    FL sizer and seater are both cut off by 0.4" and a new thread relief is turned. 

2)    Neck portion of the sizer die is honed inside up to .420" diameter to produce a tight and correct fit for loading .400” jacketed bullets, without expanding, but flaring only. 

3)    Neck portion of the seater die is honed inside to .429" diameter and the ball seat of the seater die is honed up to .402", because if it is tighter, then it really needs to be. 

4)    IF you want to cut down .44 Special cases, Doug can shorten a Lee .44 Special case holder for the Quik-Trim, by cutting 0.16" off the top. Then you adjust the Quik-Trim to cut the necked down .44 Special cases to 1.000+0.000/-0.005"

5)    Once you have fire-formed brass, it is possible to neck-size only by using a 0.525” spacer with your .40 S&W Auto dies.

...Starline .44 Russian brass comes 0.0960-0.965" long.  After necking down to .40 cal. they will be 0.970-0.975"...

We elected NOT to get an inside neck reaming die made to thin our case necks. This saved a great deal of money in development costs and case making effort. It also results in a more sturdy case which can withstand rough handling, unlike paper-thin .38-40s!..

Based on feedback Dave Manson revised the chamber neck diameter on the print and anyone ordering this reamer in the future should specify .40/.44 Special Short Harris Rev1-6/18...with... .429” neck diameter, having a .402” cylindrical ball seat 0.10” long with 6 degrees, Basic forcing cone...

10x25mm loads in Starline .44 Russian brass with 180 Hornady FMJ, Accurate 40-182H and 40-220H, again, all with 5 grains of Bullseye. The 180-grain Hornady FMJ with 5 grains of Bullseye give 932 fps with a standard deviation of 15 fps over a six-shot string.  Accurate 40-182H with the same 5 grains of Bullseye in the 10x25 gave 1009 fps, an Sd of 10 fps and shot to the sights at 25 yards, just like it did in the .40 S&W.  The 40-220H gave 949 fps with a standard deviation of 10 fps and grouped at the top edge of the black on a B15 25-yard timed and rapid-fire pistol target. Indeed, about right for a 100-yard zero. Both groups very slightly left, maybe one click to center them up.

Next step was to test the same RCBS Little Dandy #9 rotor which meters 5 grains of Bullseye, but this time metering 7.4 grains of AutoComp.  The 40-182H gave 1138 with a 10 round Sd of 14 fps, and 40-220H gave 1083 fps with a 10-round Sd of 11 and round groups.

The RCBS Little Dandy #18 rotor which fills the case to the neck-shoulder junction, without compression, was used to meter 14 grains of IMR4227. Velocity was 1033 fps with an Sd of 16 with the 40-182H bullet and 1008 with an Sd of 12 with 40-220H, with significant unburned powder and loose groups.  IMR4227 is too slow for the light bullets, but might work with heavier ones. UPDATE Dec. 24, 2018 - Little Dandy Rotor #20 meters 16 grains of IMR4227, filling the case up the neck enough to permit slight compression when the heavier 40-252H bullet is seated. - Will try in the Ruger First, STAY TUNED!

A dip measure made from a .357 Magnum case measures about 20-21 grains of Goex 3Fg or 4.2-4.5 grains of Trail Boss, filling the case “gently to the shoulder without compression.”

The maximum black powder charge is 24 grains using a drop tube or compression die. Sam’s recommended 4.5 grains of Trail Boss is a “full charge” load, with 4.8 grains being the “absolute full stop not to be exceeded,” because Trail Boss should NOT be compressed!

I tried lighter charges with Bullseye and Accurate 40-220H and 40-224H, looking to find a low recoil load of traditional black powder velocity level, approximating the .41 Long Colt.  3.5 grains of Bullseye in the 10x25 case, with 40-220H gave 760 fps with a standard deviation of only 7 fps and an extreme spread of 29 fps over a 12-shot string.  Substituting the 40-224H ogival wadcutter results were almost identical with 748 fps, an Sd of 7 and a 12-round ES of 23 fps., producing satisfying 2-1/2” groups at 25 yds.     

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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John Alexander posted this 18 December 2018

Ken,

Looks great to me.

We might more comments, questions, and wildly complimentary praise heaped on your efforts with it's own thread and title (or the old thread with Index in the title) so more folks will find it.

John

 

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Ed Harris posted this 18 December 2018

I tried to do that, but when trying to retrieve the original revolver thread to edit, I got a 404 error, which is why I posted it in this new thread.

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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John Alexander posted this 18 December 2018

Ed,

I meant Ken's index post.  I will have to ask about the 404 error.

Sorry for the confusion.

John

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Ed Harris posted this 19 December 2018

FYI,

Here is the heavy 10mm bullet Tom at Accurate is making for me to use in the Ruger/ Bunnygun combo.  OAL will be about 1.50" in the 10x25, which fits nicely in the Ruger cylinder.  My best educated guess is this is as heavy as will be stable in a 16" twist subsonic.  No mental masturbation needed, I'll simply stuff the case with IMR4227 to light compression and touch it off.  Rugers are hell for strong and make load development easy.

Expect point of impact in the revolver will be much higher than my other, lighter bullets, but probably fine for the 12" gong at 100 yards.  If it is stable and fairly accurate at 100 yards in the Blackhawk, then we try in the Bunny Gun.

Then start reducing the load to find the lightest charge which exits the 22-inch Bunny Gun Barrel, see if that is minute of beer can or clay bird at 100 yards with 4X scope.  If so, then declare Victory!  Simple.

 

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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M3 Mitch posted this 19 December 2018

I particularly like the iron sights, the military style front and the peep.  Is the peep part of the scope mount?  Is the front sight a custom job or did it come from some other factory gun? 

At first I was a bit surprised you might hunt deer with this, it wouldn't make a very good deer gun out here in the West, but back there where shots tend to be under 100 yards, I guess it should do just fine.  It would work OK out here too, provided you could get close enough, although if a guy was familiar with the trajectory it would probably be OK to 150 yards or a bit more.

For deer hunting where you might want to accomplish a reload pronto, one thing I like on break-opens and other single shots is a butt-cuff from Murry Custom Leather.  I have one on a Savage combo gun, a .22 rim-fire over 20 gauge under.  They made one up to my design that holds 5 shot shells, and 2 rows of .22, one row of .22 over the other.  It sits with a variety of .22 from CB Longs to Stingers, and 3 one-ounce #6 20 gauge shells, with two 3" "magnum" shells, I think these are #4 but maybe they are #6 too. So long as I keep calm and select the correct round, I'm good for all sorts of shots on various small game and varmints out to about 75 yards

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Ed Harris posted this 19 December 2018

The front sight is USGI from an M14.  John machined the integral base on the barrel.  He has done that on several rifle barrels for me.  Rear sight is an XS for 1894 Marlin.  Scope base is Weaver for the H&R Handi-Rifle, and rings are stock Weaver also.  We used high rings to clear the peep aperture.  For offhand snap shooting and testing loads off the bench this works fine.

I have found a butt cuff slower than having a loose round in my pocket or already in my hand.

Also messes up the snap-shooting, quick to the shot, balance of the gun.

Most shots in the woods here are 25-50 yards and over 100 is unusual. 

The .44-40 with black powder works well and is a good killer which ruins little meat.

This rig should mimick .38-40 black powder loads with the lighter bullets and approach .40/.50 Sharps Straight with full-charge smokeless loads with the heaviest bullets which stabilize in the 16" twist.  A .40 cal., 250-grain FN bullet with meplat 0.7 of bullet diameter at about 1250 fps should be a good killer and shoot through even large animals.  In my experience .44-40 penetration is better than factory in a .30-30 and you can eat right up to the bullet hole.  This should be an even better penetrator and from 1 to 30 tin-lead expand a bit and provide a great blood trail.

Tom is also making for me a 40-260H which is the same profile as the 252H above, but with the nose lengthed to 0.56," producing a 0.24" diameter meplat. 

Agree with Ric that these heavy slugs take this out of the "Bunny Gun" category and into a "Bush Buck Whacker" which imparts fear and trepidation into the back yard Black Bear.

  

 

 

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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M3 Mitch posted this 21 December 2018

IIRC, you still have the original .410 barrel, and another rifle barrel, I have read about that other rifle barrel in FS but I forget what caliber it is.  But it's a smaller bore. If you wanted to, you could make up a shotgun-style case that held all 3 barrels and with that you would have a very compact and light set up that would be good for hunting almost any North American game.  Even loaded with say bismuth shot, the .410 would, I guess, be legal for waterfowl but not really what you want for that.  The 10X25 would no doubt kill a bear if you hit it right, but I couldn't blame a guy for wanting something more in the lines of a bolt gun in 30-06 or a 45-70 Guide Gun for bear.

For small game and on up to deer this is a great setup.

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SavvyJack posted this 21 December 2018

I like it!!!

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Ed Harris posted this 21 December 2018

I have no need for a quiver full of barrels, as I have three receivers. I keep one set up with the .410 shotgun by the kitchen door for varmints.  One is usually nearby set up with barrel for a small game revolver round, usually .32 S&W Long or .38 Special, or in deer season a large bore, either a .44-40, .45 ACP/.455  or .45 Colt, as I have revolvers for all.  

Frequently carry the .410 as a snake gun when out cutting wood or clearing brush.  Rifle for woods walks with caliber selection depending upon which hunting season is in and which revolver I am carrying.

  

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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delmarskid posted this 23 December 2018

Ed don't you just love picking a firearm as you would pick out a tie? It's important not to be overly or underly dressed for the occasion. Don't forget to keep your "Emily Post" up.

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Ed Harris posted this 23 December 2018

Ed don't you just love picking a firearm as you would pick out a tie? It's important not to be overly or underly dressed for the occasion. Don't forget to keep your "Emily Post" up.
EXACTLY. 
Rural-agricultural styling with subtle "tactical" features.
Accurate 40-252H in 10x25R
Accurate 40-252H seated in reworked Starline .44 Russian case.

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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Ed Harris posted this 29 December 2018

Initial velocity checks firing 10x25R H&R “Bunny Gun” with 22-inch barrel:

Reformed Starline .44 Russian cases, .970-.975”, Remington 2-1/2 primers.

Accurate 40-182H

5.0 Bullseye______1144 fps, 17 Sd

4.9 452AA_______1082 fps,  17 Sd

7.4 AutoComp____1285 fps, 9 Sd

Accurate 40-220H

3.5 Bullseye_______832 fps, 18 Sd

5.0 Bullseye______1059 fps, 10 Sd

7.4 AutoComp____1217 fps, 7 Sd

Accurate 40-224H

3.7 452AA_______820 fps, 13 Sd

4.2 452AA_______903 fps, 8 Sd

4.9 452AA_______1002, fps 13 Sd

Next range trip will be for charge establishment with 40-252H and 40-260H

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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Johnshandloads posted this 03 January 2019

That is a neat cartridge and very cool rifle. Thank you for sharing the details, I really love things like this. 

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