Chambering both ends of a barrel - Project "Carnival Hotdog Barrel"

[LRSickle]

I'll explain the name in a bit. This might be a long post.

I was sitting at my desk, watching a bear poop outside my office window (Really! I work at a salmon hatchery) while wondering what my next gun project will be. I've had this bull barrel sitting on my desk for over a year now. It's been a great barrel. It was originally a 22-250 and shot really well. It's had the shoulder/tenon set back .004 and chambered it to 22-250 AI. [the neck/shoulder junction on Ackleys are generally .004 shorter than their parent case]. It also shot really well. But that wasn't enough so it was punched it out to a 22 CHeetah. Now that a fun caliber!! After the throat was roasted in that, I lopped off about 2" and rechambered it to 220 Swift. I thought, "I wonder how many times I can rechamber this before I run out of the minimum 1.055" diameter I need for a tenon?" Hmmmm...
I also wondered if I could chamber the muzzle end and shoot back through the barrel. Hmmmm... If I did chamber the muzzle end I wouldn't have enough shoulder for my recoil lug. Hey, I know! I'll do it Savage style with a barrel nut. I have several Savage barrel nuts laying around but they're 20 pitch and my Rem700 is 18 pitch. Hell, I'll just make my own barrel nut!
Before I knew it I was started on my new project. I was going to chamber both ends! I'd imagine somebody, somewhere has done it before but I'd never heard of it. I did a brief internet search and turned up one result that didn't have much info about it.
I thought long and hard about two things, safety and accuracy. I approached a coworker who is a very accomplished gun-plumber as well as a fine machinist. We mulled over the possibility for several days. How is the leade in the other chamber going to affect bullet flight? Muzzles are pretty precise. The bullet needs to clear all the lands and grooves at the same time or it's blown(?) off course. Accuracy I didn't care too much about but it had to be safe. I couldn't foresee any problems with safety. It turned out I was wrong, kinda, I'll get to that as I go along.
It's all done. I've shot through both chambers and lived to tell it. I learned a lot and found some pretty surprising things.

When a co-worker came in the shop and ask what I was doing, I told him I'm making a "Carnival Hotdog" barrel. This barrel is just like finishing a hotdog at the carnival, when I'm done with it I'll be shooting out of both ends.

 

[LRSickle]

I chamber barrels with the through-the-headstock method. This barrel would be too short to clamp in my chuck and spider at the same time. Soooo, I made an extension out of a huge bolt used to anchor beams and pilisters to concrete foundations. I made one end of the bolt into a replica of my Rem 700 action and screwed the barrel to that. I also planned on parting that end off later and using it as a thread protector.

Here it is mounted in my lathe. I'm getting ready to part it off at the redneck Dykem (sharpie) mark (1.055 dia). This picture shows the spider with the brass screws in the back.

 

[LRSickle]

Most of you guys know this drill but I posted the pictures of the chambering anyway.

I also have the barrel nut on the threads. I made the nut out of...what else, an old stainless bolt.
I'm getting ready to chamber it. I use a hand-held reamer wrench and the tail-stock as a pusher. I don't chuck the reamer in the tailstock because I don't have a floating reamer holder and I don't trust the quill to be in perfect alignment with the barrel bore. If the quill is off, the diameter of the back of the chamber will be out of spec.

Here I have the tenon threaded Savage style with a Remington style bolt recess.

 

[LRSickle]

Savage style setups are a pain in the *** to headspace with a Remington bolt and breachface. I have to set the boltface and tenon clearance each time I check the progress of my headspace. I was shooting for .005" clearance. I ended up with .006". I probably took it apart and put it back together 20 times. When I get close to the final headspace I try to "sneak up on it." I don't want to go over!

 

[LRSickle]

Here's the barrel finished at 11 1/4"

Here it is with it's "thread protector" installed. I took the thread protector off at the last minute because I wasn't sure what kind of effect an open chamber would have being capped off with a 3/8th hole. Would there be some kind of echo, reverberation or pressure build-up?? I didn't know.

 

[LRSickle]

So did it shoot good? HELL NO!!! BUT IT SURE WAS LOUD!!!I'm sure shooting out of the throat of the other chamber had something to do with it. I suspected it would.
I hit the target one time out of five with the first chamber at 100 yards and the bullet went through sideways. I moved up to 40 yards and hit it two more times out of five. Two went through sideways and one was "tipping".

 

[LRSickle]

So off I hiked for home to swap the barrel around and try the other chamber. Did the other end shoot any better? NOPE!!!
This time I went right to 40 yards and took 10 shots. I only hit it 7 times and all bullets keyholed. I'm using a lighter load than I used with the original barrel length. According to Sierra's manual it's shooting 3500 fps. A leisure pace for a Swift but still fast enough for a 55gr Blitzking to stabilize in this barrel.

 

[LRSickle]

With a flashlight, I could see both chambers had three weird carbon bands in them. So after work I mounted the barrel in the lathe and parted one of the chambers off and cut it in half. I have no idea what caused this. An echo? Some kind of reverberation? Did it have something to do with how inaccurate it was?

 

[LRSickle]

Next, I recrowned the end I'd parted the chamber from. I wanted to see if it would return any kind of accuracy. It didn't.

 

[LRSickle]

My first shot dented the aluminum shim stock I put in the barrel channel to protect my Tupperware stock from heat. It's super thin and malleable. I was surprised but I wasn't too alarmed.

 

[LRSickle]

However... my second shot was a wakeup call! That's it, I'm done. I took it back to the shop, yanked the barrel and cut it in half length-wise.

 

[J E Custom]

However... my second shot was a wakeup call! That's it, I'm done. I took it back to the shop, yanked the barrel and cut it in half length-wise.

I have but one question, what were you trying to do or prove, (Not trying to be a smart *** just asking a question)

I think I know the answer to the poor accuracy issue though. The chamber makes a very poor crown and shock waves should cause the bullet to yaw and the reverse lead angle cant be good for the jackets.

I am surprised that the short barrel did not shoot well after the chamber was cut off but with the muzzle blast destroying the stock, I'm guessing that you lost interest in trying to find out if it was accurate. also In a normal barrel length, exit pressure of the gas is around 15,000 to 18,000 psi. The exit pressure of the gas on such a short barrel was probably around 50 or 60,000 PSI , so the blast would be terrible.

Please share any observations you have on this project with us if you will.

J E CUSTOM

 

[J E Custom]

Come to think of it, I saw an article once that a guy tried something similar to what you did thinking that He could use one barrel and do a switch from one cartridge to another simply by switching ends of the barrel on one barrel and save even more money than a switch barrel setup using 2 different barrels on the same action and stock.

He was not as forthcoming as you were and just said it didn't work very well.

Glad you weren't hurt.

J E CUSTOM

 

[Timnterra]

I'd be carful sharing this with the inter-web. I don't think anyone would or could say anything to you about having built an SBR, now that it is destroyed, but on the other hand the stupidity of people never ceases to amaze me.