32 ACP rifle?

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  • Last Post 09 September 2011
Lefty posted this 16 January 2010

I have watched the various Bunny gun and other 32 ACP threads for a while now but Ed Harris just really pushed my button.  Converting a Remington 580 to 32 ACP?  Please tell me more.  Difficulty? $? Anything you got!

Are there other successful 32 ACP bolt guns out there?  Please share.

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mike morrison posted this 16 January 2010

my thoughts also. please share ed. thanks.

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Ed Harris posted this 19 January 2010

Here is the info.  For .32 ACP we are going to use a pinned barrel, made from a 10 inch twist Douglas .308 groove, because we are interested in low velocity, low noise “cat sneeze."  We want the .32 ACP case for its tiny capacity for minimum airspace, and good ballistic uniformity with clean burn in subsonic loads.  We are not trying to see how hot we can load it, as this defeats our purpose.  

Gunsmith will make new bolt head, and not enlarge the ejection port, as this is unnecessary with the tiny ctg.  Having done so parts could be restored to .22 LR I ever wanted to.  

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 19 January 2010

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

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RicinYakima posted this 19 January 2010

Thanks Ed! Looks like a great project for some winter! Ric

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Lefty posted this 20 January 2010

Ed

Thank you, this is great.

Jim

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Reg posted this 21 January 2010

Thank you, will add this to my project list for sure. Now dumb question. Has anyone tried this concept using the 25 ACP case ? Thanks Reg

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Ed Harris posted this 21 January 2010

.25 ACP is an oddball .251 bullet diameter, no advantage that I can see.

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

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Reg posted this 21 January 2010

I havn't played with it I admit but would you have a wacky looking case if you used light .257 dia cast heads ??

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Ed Harris posted this 09 July 2010

The rifle is back.  First picture below Andy Evans. Barrel chambered and bolt headspaced, still needed to fit extractor, make cut extractor slot, drill firing pin hole and fit CF firing pin and blue.

Followed by 25 yard groups with 88-grain NEI #82, 2 grs. of Bullseye.

Followed by closeup of altered centerfire boltface.

And a photo of the rifle with 4X Bushnell scope on it.

And a final bragging target fired at 25 yards, center hold on bull with Privi Partisan 71-gr. FMJ and 12:00 tangent hold with the NEI 88-grain flatnose #82

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 23 July 2010

Next is to see how heavy a bullet I can get to chamber and stabilize. Going to try 115-grain version of NEI #82 with a half-charge, 1 grain of Bullseye. In the 10-inch twist it should stabilize OK and be like a CB cap on steriods.

SCROLL BACK to see latest pics I pasted into previous.

 

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

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Mike H posted this 03 August 2010

Most impressed with this project Ed. What length barrel did you end up with ?, and how would you rate the noise? say in comparison to various .22 rimfire rounds. Hope to hear more of this rifle. Mike.

 

 

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Ed Harris posted this 04 August 2010

Barrel length is 22 inches. 2 grain load of Bulleye was most accurate, but slightly noisy because some rounds go supersonic in the rifle length barrel.  Instead am standardizing on minimum charge which reliably cycles my Walther PP. With charge reduced to 1.7 grs. of Bullseye with 88-grain NEI #82 I get 850 f.p.s. and inch groups at 25 yds. Report is similar to standard velocity .22 LR from sporting rifle.  No crack, only a pop and smack when bullet hits.  Peak noise was measured 85dB at 1 metre from the muzzle. Noticeably quieter is “heavy bullet CB cap” using 115-gr. NEI #82 and tiny charge only 1 grain of Bullseye, about 600 f.p.s., for 74dB, like firing subsonic .22 LR with a “can".

Full length NEI #82 as pictured below with GC heel weighs 122 grs. in linotype and 130 grs. in 1:25 alloy.  My standard .30-30 plinker, also good in .303 Brit and .30-40

115-gr. version removes GC heel leaving two grease rings and three driving bands.

88-gr. version removes GC heel, bottom band and grease ring leaving two driving bands and one grease ring.  Bore riding nose casts .303+ and engraves in most .32 ACP barrels. 

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

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Mike H posted this 04 August 2010

Thanks Ed.

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Ed Harris posted this 10 August 2010

50 yard group fired by Paul Kalland shows effects of barrel conditioning.

5.4 grs. of #2400 is a nominal caseful and “cracks"  not for handgun use.

I like my “.30 cal CB Cap” loads alot better.

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

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NoZombies posted this 03 November 2010

Ed, any update on the rifle?

It looks like I'm getting one that was completed some time ago in .32 S&W long caliber, and based on the 581, so, slightly different in specs, but certainly similar in concept.

What's the favorite bullet design for the 1-10 twist at 900-1000 +/- FPS, if you don't mind me asking?

I ask, because I'm getting it as an almost complete project that someone else wasn't able to get to shoot. The twist is most likely about 1-10, but until I have it in my hands, I'm not entirely sure.

Any thoughts or comments?

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Ed Harris posted this 03 November 2010

The .32 ACP rifle follows true to form of the other bunny guns delivering inch 5-shot groups at 25 yards and in proportion at 50 yards.  That seems to be the limitation of cast handgun bullets.  The scope makes groups more consistent, but the ammo is the limiting factor.  So these guns are not as accurate as a good .22 rimfire shooting match grade ammo, but they are effective on small game at modest ranges and lots of fun to shoot.  The most accurate, quiet load is the 115-gr. NEI #82 plainbase with 1.5 grains of Bullseye for 820 f.p.s. in the rifle.  I call it my “.30 cal CB Cap” and it's about that loud.

If previous owner of your .32 S&W Long rifle “couldn't get it to shoot” the first thing to look at is the throat. The SAAMI chamber for the .32 S&W Long is based on the revolver chamber and has an abrupt transition from about a .336 diameter at the case mouth, to a cylindrical ball seat, typically .314-.315 diameter about as long as its diameter. The front of the reamer next to the pilot is only a 45 degree chamfer, which if run into a rifle type barrel, leaves an abrupt start into the rifling.

A reamer intended for use in a single-shot rifle or pistol such as the T/C Contender will have a more gradual transition from the case mouth and either a normal rifle-style cylindrical ball seat of bullet diameter, for a length typically about 1/10 to 1/8 of the bullet diameter, and a gradual forcing cone, typically 6 degrees included angle. Another common form follows the style of the .38 AMU chamber used to convert .38 Super auto pistols to .38 Special wadcutter. This simply has a 1-1/2 degree basic forcing cone departing directly from the case mouth, with no cylindrical ball seat. This form also shoots well with lead bullets.

If you have the revolver style chamber with very long cylindrical ball seat and abrupt start of rifling, you will have best results with long-bodied bullets seated out. I use the NEI #82 in my chamber of this type. While my single-shot rifle started with a .32 S&W Long revolver chamber, I later run a .32 H&R Magnum reamer in to enable use of that brass and to shorten the cylindrical throat some. It shoots inch groups at 25 yards seating either the 115-grain plainbsed, or 130-grain gaschecked NEI #82, or the 120-gr. Saeco #322 out and crimping in the top lube groove in .32 S&W Long brass, or in the normal crimp groove when using .32 H&R Magnum brass.

The 130-grain NEI #82 with GC is the heaviest bullet which will stabilize in the Marlin 1894CB rifles with 20 twist of rifling. In a 10-inch twist try Saeco #630 140-gr. plainbase, or #315 175-grqain flatnose GC, seated out to touch the rifling with all the RL-7 you can get into the case without compression.

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

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NoZombies posted this 03 November 2010

Hey Ed,

Thanks for the tips, I'll have to take a close look at the throat and bore when I get the rifle. In talking to the man I'm getting it from, the chamber was cut with a custom gunsmith made D-reamer, so there are a lot of unknowns there. The same smith did the CF conversion, so I'm hoping his work will be okay.

I'm curious about the accuracy you mentioned, I've got a .32 rimfire falling block that will do very nice cloverleafs at 50 yards with my dwindling supply of 1970's vintage Cannuck ammo. When my ammo runs out, I'm planning to convert it, or have it converted, to CF and chambered for .32 S&W long.

Do you suspect that RF will become less accurate with the conversion? I intend to shoot cast bullets between 80 and 110 grains through it in it's .32 S&W L guise. Do you think perhaps the lack of better accuracy in the bunny guns has to do with the tight twist not being ideal for the short pistol bullets? Not to say that the guns aren't accurate enough, but I wonder if they could be more so with a slower twist?

Correct me if I'm wrong, but I believe the old standard for 32-20 was 1 in 18 and later was updated by some manufacturers to 1 in 16.

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Ed Harris posted this 04 November 2010

NoZombies wrote: Thanks for the tips, I'll have to take a close look at the throat and bore when I get the rifle.... I'm curious about the accuracy you mentioned, I've got a .32 rimfire falling block that will do very nice cloverleafs at 50 yards with my dwindling supply of 1970's vintage Cannuck ammo. When my ammo runs out, I'm planning to convert it, or have it converted, to CF and chambered for .32 S&W long. Do you suspect that RF will become less accurate with the conversion?... I Not to say that the guns aren't accurate enough, but I wonder if they could be more so with a slower twist?...Correct me if I'm wrong, but I believe the old standard for 32-20 was 1 in 18 and later was updated by some manufacturers to 1 in 16.

I'm not sure it is as much a matter of twist rate, but of bullet quality and proper fit.  The quality of swaged bullets in rimfire ammo is very good, better in terms of dimensional uniformity and roundness than typical cast pistol bullets.  They are also soft, seal the bore well, are well lubricated, and used in light, low pressure loads with fast burning powder.  I have tried to maintain those parameters in my bunnygun loads and have done best when I did.

As for twist, I have shot .32 bunnyguns in twists from 10 inches all the way to 20 inches and almost everywhere in between.  Accuracy with light bullets and loads was not materially different, however, the faster twists let you shoot very light loads with heavier bullets.

In .32-20 revolvers I have encountered twists of both 16 inches and 18 inches, and in handgun use, based on my experience with the .32 S&W Long the faster twist is better.  My most accurate .32 revolvers have been a Colt Officer's Model Target in .32 NP which had a 14 inch twist, and a custom S&W K32 I had built recylindernbg and rebarreling a .38 Special, which used a 14 inch twist Obermeyer tight-bore .298x.308 Palma barrel. 

In .32-20 rifles the most common twist is 20 inches, which is used in the Savage Model 23 boltguns, 219 single-shot, and the Winchester 92.  A 20 inch twist was also used in the Winchester .32 self-loading and the .30 M1 carbine.  In a rifle I would worry less about twist than in getting a good quality barrel, cutting a good chamber in it and casting match quality bullets that fit.

The most accurate .32 S&W Long rifle I ever shot was a Remington Model 788 which Ellis Lea had, which had an 10-inch twist Hart barrel on it and long, gradual Ardito-style throat, in which he used the Saeco #315 breech-seated with a compressed charge of RL-7, about 8 grains, and Federal 205M primers.  This rig drove bugholes at 100 yards and had the same trajectory as a .22 match rifle. Velocity was subsonic.

Using handgun ammunition it shot no better than I am getting. You have to decide whether you want a bunnygun which is a fun plinker with ordinary loads, or if you want something so specialized that it isn't suitable for hunting, and requires tweaked ammo which you cannot use in your revolver.  I think that defeats the purpose. 

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

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NoZombies posted this 05 November 2010

Thanks Ed, food for thought.

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pavementends posted this 08 September 2011

Ed,        Any thoughts on a 581 in 9mm? Kind regards Kent

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Ed Harris posted this 08 September 2011

A 581 in 9mm or 7.62x25 could certainly be done. More elegant than a black carbine. It would give the option to use full-power servcie loads, or to down-load for low noise. Potentially very useful.

It would be intersting to try a 140-gr. 9mm cast bullet with a very light charge of fast burning pistol powder, say 2 grs. of Bullseye for a rifle velocity of about 800 fps. It would hit like a .38 Special but be quiet.

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

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pavementends posted this 08 September 2011

Ed,     Thank you for your reply.  The ability to use full power factory loads or lead bullet loads for a fairly quiet plinking load strikes me as a fun rifle.      Any suggestions as to twist? Kind regards Kent W4ETT

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Ed Harris posted this 09 September 2011

I would go with a 14 or 16 inch twist if I could find one, but quality of the barrel is more important than twist rate. If you find a really high quality 10 inch twist affordably, use it.

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

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