Homebuilt 12 ga Hull Trimmer

FrankenMauser · February 15, 2012, 03:38 AM

I recently got a smoking deal on some new primed 12 ga 3" Winchester high brass (AA) hulls, that were cheaper than I can buy just primers. There was a problem, though... my only 12 ga shotgun has a 2-3/4" chamber. I cannot use 3" shells, and have no plans to buy another 12 ga shotgun, any time soon.

So, I tried trimming the shells by hand, by using the handle of a Lee Ingot Mold as a cutting mandrel. That didn't work well, at all. I tried using a tubing cutter, while still using the Lee handle as a mandrel. That was better, but not precise. I toyed around with a few other methods, but they were even worse than the Lee handle and various cutting devices.

In the end, I had 15 shells that were too short to properly star (fold) crimp as 2-3/4" shells, and just as many that were terribly uneven. So, I decided to cut them back to 2" and 2-1/2" shells; but I wanted it to be precise and consistent. I also wanted a tool that would let me cut the rest of the new hulls, without totally screwing them up. However... Commercial hull trimmers are too expensive. I simply cannot justify the cost, for the meager amount of shot shells I need to trim.

I decided to build my own trimmer, using only what I had laying around, except for a store-bought 3/4" poplar dowel.

The square tube was left over from my garage door opener replacement. The aluminum channel and hardwood base were left over from my reloading bench build (new bench, still in progress). The hose clamps are from "shop stock" in my miscellaneous car repair bins/boxes. The metal bracket and "lever" were salvaged from a computer that was recycled. The hardware was just left over crap I've had laying around.

The dowel was sanded by hand, until various Federal and Winchester hulls would slip over it, without too much effort (including off-brand hulls of similar construction). Because Remington hulls have thicker walls, I simply decided I would never trim them with this device. After all; why compromise the precision of the tool, for one type of hull that I rarely encounter, anyway? The re-contoured dowel serves as the cutting mandrel. It was finished with 300+ grit sand paper, for effortless spinning of the shells.

The mandrel is adjustable (inside the aluminum channel), to adjust the length of the hulls. And the razor blade is adjustable for cut depth.

Usage is simple. Once the mandrel is adjusted to provide the correct hull length, I grab the body of the tool (over the hose clamps) with my left hand. Slight pressure is applied to the cutting blade, while I spin the hull with my right hand. In less than 3 revolutions, it will cut right through brand new hulls. Fired or skivved hulls are cut even faster. It really doesn't take much pressure, with a sharp blade.

In no time at all, you have a clean, straight cut.

As always... I just thought I'd share. What tools have you built at home, because you couldn't afford the commercial version, or didn't like the way it worked?

Uncle Buck · February 15, 2012, 08:20 AM

That is pretty cool.

griz · February 15, 2012, 08:28 AM

That's pretty slick, good job!

I don't have any pictures, but my home made hardware also was to shorten cases. For cowboy action I wanted some cases that were 38 S&W length. I made a block that was the thickness of the distance from the top of the rim to the mouth of the case, drilled a .38 hole in it, and used it to trim 38 special cases to a consistent length. It worked well for the couple dozen cases I needed.

Rottweiler · February 15, 2012, 08:30 AM

Nicely done!

jaguarxk120 · February 15, 2012, 10:20 AM

Hey, a great setup, easy to adjust and over the counter cutting blades.

Sevens · February 15, 2012, 12:09 PM

That is very, very cool.

Question, though-- is it difficult to crimp a shell that doesn't have a factory crimp started because it's been chopped off? I haven't dabbled in shotshell in (jeez, has it been that long) two decades, but I can't see it being easy to make a crimp where there is none, and I'd be worried about how well it stays closed.

FrankenMauser · February 15, 2012, 03:50 PM

Sevens-
I haven't had any issues. It is supposed to greatly reduce problems and effort required to crimp, if the hulls are skivved. But... I have been crimping these in their unskivved form, without a problem. I do give the crimp about 4-5 seconds to set in the die, though. Once the crimp is formed, it holds much tighter than reloads.
(I think it would probably be easier to use a 6-point crimp, but I've been sticking with an 8-point, since these are Winchester hulls.)

February 15, 2012, 03:38 AM	#1
FrankenMauser Senior Member Join Date: August 25, 2008 Location: In the valley above the plain Posts: 13,424	Homebuilt 12 ga Hull Trimmer I recently got a smoking deal on some new primed 12 ga 3" Winchester high brass (AA) hulls, that were cheaper than I can buy just primers. There was a problem, though... my only 12 ga shotgun has a 2-3/4" chamber. I cannot use 3" shells, and have no plans to buy another 12 ga shotgun, any time soon. So, I tried trimming the shells by hand, by using the handle of a Lee Ingot Mold as a cutting mandrel. That didn't work well, at all. I tried using a tubing cutter, while still using the Lee handle as a mandrel. That was better, but not precise. I toyed around with a few other methods, but they were even worse than the Lee handle and various cutting devices. In the end, I had 15 shells that were too short to properly star (fold) crimp as 2-3/4" shells, and just as many that were terribly uneven. So, I decided to cut them back to 2" and 2-1/2" shells; but I wanted it to be precise and consistent. I also wanted a tool that would let me cut the rest of the new hulls, without totally screwing them up. However... Commercial hull trimmers are too expensive. I simply cannot justify the cost, for the meager amount of shot shells I need to trim. I decided to build my own trimmer, using only what I had laying around, except for a store-bought 3/4" poplar dowel. The square tube was left over from my garage door opener replacement. The aluminum channel and hardwood base were left over from my reloading bench build (new bench, still in progress). The hose clamps are from "shop stock" in my miscellaneous car repair bins/boxes. The metal bracket and "lever" were salvaged from a computer that was recycled. The hardware was just left over crap I've had laying around. The dowel was sanded by hand, until various Federal and Winchester hulls would slip over it, without too much effort (including off-brand hulls of similar construction). Because Remington hulls have thicker walls, I simply decided I would never trim them with this device. After all; why compromise the precision of the tool, for one type of hull that I rarely encounter, anyway? The re-contoured dowel serves as the cutting mandrel. It was finished with 300+ grit sand paper, for effortless spinning of the shells. The mandrel is adjustable (inside the aluminum channel), to adjust the length of the hulls. And the razor blade is adjustable for cut depth. Usage is simple. Once the mandrel is adjusted to provide the correct hull length, I grab the body of the tool (over the hose clamps) with my left hand. Slight pressure is applied to the cutting blade, while I spin the hull with my right hand. In less than 3 revolutions, it will cut right through brand new hulls. Fired or skivved hulls are cut even faster. It really doesn't take much pressure, with a sharp blade. In no time at all, you have a clean, straight cut. As always... I just thought I'd share. What tools have you built at home, because you couldn't afford the commercial version, or didn't like the way it worked? __________________ Don't even try it. It's even worse than the internet would lead you to believe.

February 15, 2012, 08:20 AM	#2
Uncle Buck Senior Member Join Date: June 21, 2009 Location: West Central Missouri Posts: 2,592	That is pretty cool. __________________ Inside Every Bright Idea Is The 50% Probability Of A Disaster Waiting To Happen.

February 15, 2012, 08:30 AM	#4
Rottweiler Senior Member Join Date: January 30, 2001 Location: Texas Hill Country Posts: 391	Nicely done! __________________ Texas - envied by lesser states since 1845

February 15, 2012, 12:09 PM	#6
Sevens Senior Member Join Date: July 28, 2007 Location: Ohio Posts: 11,756	That is very, very cool. Question, though-- is it difficult to crimp a shell that doesn't have a factory crimp started because it's been chopped off? I haven't dabbled in shotshell in (jeez, has it been that long) two decades, but I can't see it being easy to make a crimp where there is none, and I'd be worried about how well it stays closed. __________________ *Attention Brass rats and other reloaders:* I really need .327 Federal Magnum brass, no lot size too small. Tell me what caliber you need and I'll see what I have to swap. PM me and we'll discuss.

February 15, 2012, 03:50 PM	#7
FrankenMauser Senior Member Join Date: August 25, 2008 Location: In the valley above the plain Posts: 13,424	Sevens- I haven't had any issues. It is supposed to greatly reduce problems and effort required to crimp, if the hulls are skivved. But... I have been crimping these in their unskivved form, without a problem. I do give the crimp about 4-5 seconds to set in the die, though. Once the crimp is formed, it holds much tighter than reloads. (I think it would probably be easier to use a 6-point crimp, but I've been sticking with an 8-point, since these are Winchester hulls.) __________________ Don't even try it. It's even worse than the internet would lead you to believe.

February 15, 2012, 08:28 AM	#3
griz Senior Member Join Date: July 31, 2000 Location: Middle Peninsula, VA Posts: 1,588	That's pretty slick, good job! I don't have any pictures, but my home made hardware also was to shorten cases. For cowboy action I wanted some cases that were 38 S&W length. I made a block that was the thickness of the distance from the top of the rim to the mouth of the case, drilled a .38 hole in it, and used it to trim 38 special cases to a consistent length. It worked well for the couple dozen cases I needed.

February 15, 2012, 10:20 AM	#5
jaguarxk120 Senior Member Join Date: February 28, 2008 Location: Michigan Posts: 2,620	Hey, a great setup, easy to adjust and over the counter cutting blades.