How to stub a barrel?

[tykempster]

The 50-140 post with the link to a very cheap 50 caliber barrel has the cartridge weighing heavily on my mind.  Although I'm saving for college, this still seems a very viable project.  I have a gunsmith friend who would probably enjoy this a lot, plus he has plenty of machinery.

Is there any chance there is a "step-by-step" stubbing guide?  This would help me understand the process 100%, and also be able to show the smith exactly what I mean.  It sounds fairly simple, but I'd just like to be sure.

If this goes as smoothly as it does in my mind, I'd be lobbing some surplus BMG bullets at respectable speeds once I have a bit of cash. 

[S.E.Ak]

If your smith don't know I would fine one that did for the job

[NFG]

Ditto that....it isn't rocket science and nothing more than threading and chambering a barrel and receiver.

Find a chrome moly donor rifle barrel or 10-12 ga shotgun barrel.  Cut the lug carrying section to 3-4" depending on if the barrel is tapered or straight...I would use a straight, untapered donor barrel, saves matching the tapers...thread the barrel...I like 20 to 32 TPI, thread the stub section a few thou longer so you have some meat to adjust headspace, screw together, set headspace, chamber carefully.

Leave stub shank walls 0.100" - 0.125".  There is plenty of strength even in the shotgun walls to carry any pressure load and more than plenty in the chamber walls.  While the donor barrel walls carry some of the pressure load, the chambered barrel is the main character and for the pressure you will be running you have way more than a 2X safety window.

The stub shank and barrel can be threaded full length but about 1" is sufficient...no different than a regular bolt gun receiver threaded section which usually runs from about 5/8" to 1 1/4.  Again...not a difficult thing to do for a "real" machinist.

Larry posted several pictures of his stub barrels, and there are/were several gunsmiths on the web that did stub barreled conversion...do a search and get your gunsmith to look at them...one picture is worth how many words...if he can't figure out how to do it from those "visual aides"  I would start to wonder.

It is a good project...BUT for the cost of dies and brass. 

I almost ordered one of the tapered barrels as the chylinder barrels were gone, but I want a longer barrel so I will wait...besides the twist is TOO slow for the 2.3" and longer 50 cal Mil and target bullets at the velocity you would expect in a 50-140 NEF platform...you really need something in the 1-15" twist range...that 1-24" is great for round balls or shorter bullets(1.5" bullet length optimum at 1500fs in 1-24") with BP and that is what that barrel was originally set up for.

Luck

[quickdtoo]

There are pics of one of Larry's stub projects in the FAQs.

Tim

[Smokin Joe]

Ty, NFG is right on the money re: stubbing (as always  )

Just for info, my .50-90 using the 4140 blank stabilizes up to 500 gn bullets down to 1000 fps just fine. The long 50 BMG slugs are going to have real trouble with the 24" twist, and you would have to throat the hell out of the chamber.
 I just bought one of the stainless tapered blanks (# 982460) for 38 bucks. I'm trying to decide whether to go with a .50 muzzleloader or another '90, or something else.

Decisions, decisions...............

Maybe something like this, for jack rabbits.................

[tykempster]

I never even thought about the twist...looks like I need to find a cheap 50 caliber barrel with a faster
twist.

As for the gunsmith thing, I'm 100% sure he would have no problems, he's done much more intensive work.  I just wanted to know the process myself in order to not sound like an idiot when talking to him.

[NFG]

The web if full of stubbing articles and pictures...many ways of doing the stub and barrel.

McGowen barrels are about the least expensive 50 cal bbls I've found...that's what I have on my 510 Makatak...1-15...He has several different twists available...$155 for a cylinder 1.250" x 30, $30 bucks or contouring...check them out.

Smokin Joe...how did that SS blank look?  I'm still thinking on doing some 50 cal stub...there are several very good ones using Lapua/RUM/Rigby cases that will do everything the 50-140 will do on the NEF frame and a lot less cost...or just do a longer barreled 499 HE.  The 50-140 just LOOKS and SOUNDS meaner than say a 500 AR...hahahahahaha

I've been trying to decide if a Savage prefit bbl would work using a SB2 Ultra frame and a 10-12ga stub barrel.  That would leave pretty thin walls on the stub, but plenty of meat in the barrel.  I'm going to do a mockup in aluminum to get a visual...the number crunching says plenty OK for 45KCUP and a 4"-5 stub should be plenty of barrel support even at roughtly 0.070" walls.  A good gunsmith wouldn't have any problems doing the lathe work

If this would work that would open up a whole new world of opportunities as long as the pressures were kept proportional.

Just a thought right now.

Luck

[Smokin Joe]

how did that SS blank look?

I don't have it, yet; it's supposed to get here on the 14th. I've just got to figure out how it's currently threaded before I make a decision on it:



I took a stub down to .080 in a .356 Win a couple of years ago and it worked perfectly. I like to go .125 or better these days to get a good thread purchase.

[Smokin Joe]

Here you go, Ty:



"G.I. barrel with good to very good condition bore. Outside surface includes significant rust and moderate to heavy pitting. Sold as is."  Product No. 1194390 $49.95

[tykempster]

Thank you Smokin Joe, look like just what I need.

NFG, do you suppose 40k pressures would be fine with a stubbed 50-140?

[Smokin Joe]

The breech thrust would be about 96% of a full-house .500 S&W

[NFG]

That GI barrel should have a 1-15 twist...just perfect...rust will buff off....better grab it Ty, or some scuzzzz like me WILL....hahahahahaha...Rat's, I missed that one.   WHOOPS...THAT'S ONLY A 30 CAL BARREL...Very N/G

I don't foresee any problems at that pressure...but I wouldn't push it too much more...the case is about 0.020" larger at the base OD above the rim than the 500 S&W and it is rated a bit higher pressure wise.

With that large a case you might get the cases sticking before the pressure gets too high, but I wouldn't use case sticking as an indicator unless you know the pressure us well within safety limits.  Some loads would stick cases in my 45-120 with certain bullet/powder combinations and not stick with the same bullet and other powders...burning rate, where the pressure spike is in relation to burn time, barrel length and bullet resistance all come into play.  Might have been something else causing the sticking also, that I missed.  Easy enough to do if you get a brain phart during the process.

I crunched some numbers a few minutes ago and as long as you use something in a 41XX barrel material the "bust a gut" number is over 2.5X what the frame will handle...well into the 120KPSI numbers.  NEF frames are always the limiting factor...for the most part.  You will run into the recoil problem also around 40KPSI also with heavy bullets, most likely.

Ed's 499HE uses a bigger case at a lower pressure but it still ratio's out like Smokin Joe indicates.

I dug out a Savage stub barrel piece I used to checkout feeding using a Gibbs case in a Sav LA and found a piece of tubing I can turn and thread just to see how the Savages 1.055" OD x 20TPI looks...I'll play with it tomorrow.

From the drawing and crunching the numbers and the 1.21" OD measurement from my 12GaFH USH I came up with an average wall thickness of 0.09125"(average of major and minor diam's) which will carry a Savage prefit without even blinking...and would handle the 40KCUP by itself, so adding the chrome moly barrel is just icing on the cake. All I have to do is scrounge a real CHEAP 10-12 ga shotgun barrel to make it happen...I got a ton of Savage barrels scattered all around just wanting to be wanted. 

0.080"...man that is getting a bit thin, but as it is only a carrier, not a hammer, it just looks a bit puny.    How did the 356 work?  Did you try any 358 cases?  My Marlin 336 356 works with ANY formed case with the .473" base...I tried about a dozen different sizes including metrics...stated a big HooHaa without even trying or meaning to on one of the levergun forums...sheesh...we're a cranky lot.  Hahahahaha

Luck

[Smokin Joe]

The 356 worked just fine; I never tried any 358 cases..........traded it for a .38-55.

[tykempster]

I'm debating between this, or the possible 20 gauge 3.5" "600 Nitro" I could do off a slug barrel.  The cost would be similar...hmmm, tricky thoughts running through my head.

[NFG]

Yes...the 615 *ellBoy is very doable...if you do that one be sure to slug the barrel first, BEFORE getting your bullets...NEF's are reported to have a 0.620" bore so you would actually have a 620 *ellBoy.    That one is on my back burner also, but Murphy schat on my head again so that project is a year or more off...if that is even possible.

Buying a new 20ga heavy barrel is the way to go as the cost of just doing the barrel doesn't compute.  I crunched the numbers already and there is only a $7 dollar difference...getting all those extra pieces and parts for 7 bucks is the way to go.

You've found all that good info on AA already so go for it...die prices are the fly in the pie again...cast and jacketed bullets are obtainable with a little effort.


Another kink...the prefit Savage barrels will work, BUT, they will need some additional lathe work...the threaded portion on the barrel isn't long enough just to screw it on and go banging...but...only a very little lathe work is required and once done it will be no more difficult or time consuming than swapping barrels on a Savage rifle.

Or...have a gunsmith setup a stub barrel, thread and chamber for use with a "NUT" and have exactly the same thing  AS a Savage rifle.  I've done several barrels this way for Rems and Rugers.  The nut can be round with a flat on the bottom, a simple wrench made to lock the nut, and the forend fitted to cover the flat...I did that on one Ruger...matched the flat receiver side and nut sides.  Just perfect for obtaining  ZERO headspace although the 'smith needs to be very judicious setting it up for the extractor and you will need to keep the different caliber case heads the same.  Forgetting about the extractor and going with a manual extractor(small screw driver with bent blace and barrel notch) would make it much simpler and give you more support below the case head where the ejector now sits and makes it much easier to mill an "case removal notch".

Simple ideas who'es times HAVEN'T come yet...hahahahahahahah...I know, I'm spacing...these ideas are for the more advanced "spacey-man". Hee, hee, hee.

Luck

[Smokin Joe]

Just a note re: the stainless blank:

First, let me say that this one is the best blank I've ever received from GPC

OAL:  26"
Muzzle: .865 Flat, no crown
Breech: 7/8 (threaded)
Plug: 209, 5/8 x 18 (included)
Bore: .500 / .510 1: 24" twist (shiny as a new penny)



The barrel is internally threaded 5/8 x 18 starting .348 from the breech, to receive the plug

[NFG]

Shhhh...don't tell NOBODY...very definitely full of potential.  The 0.953" section is a bit small in the OD. but usable at least for a 28-32TPI, but the rest is great for a stub OR another Savage Switch barrel.  Guess I can afford it if I eat a little lower on the hog for awhile....

Thanks for the info.

Luck

[tykempster]

NFG, for close to the same price I could have a Savage 210 receiver, could that handle the same amount of pressure as a Handi?  There would be no reason to run pressures high at all with a caliber of that size, recoil would limit me first, but, I could possibly have a mag fed rifle, with a more friendly stock design and such.

How long is the mag box on such a gun?  I probably couldn't fit a "full length" shell in the magazine, but maybe a short shell, ala 45-70 in a 45-90, etc.

[NFG]

The Savage 220(now) is running about $500...I can buy an NEF 20Ga rifled slug gun for $178 at BiMart...it will cost you 100 bucks, I'm guessing either way, to have either chambered to 3.5" so unless you can find a used, cheap 210, and I've tried, you're going in the wrong direction as far as money goes.  Pressure wise,  you can get a little more out of the 220/210.  Ed H on Accurate Arms has all the skinny on the Savage and the Mossberg 695 sluggun.

We are discussing NEF's on this forum, but if you are interested in a bolt gun I would go with a Savage Edge or the cheapest WallyWorld Savage magnum bolt face rifle without hesitation and just do a standard large bore barrel job...McGowen has barrels up to 50 cal for $155 (plus $30 for contouring) up to 30" if you want a cylinder.  I've been doing Savages since the 60's...I will probably order a 30" 50 cal barrel and do another 510 Makatak for a savage receiver.  

You can still find a Lazaronni Savage now and then on one of the gun auction sites, and the standard magnum Savage can be fitted with an OEM 375 H&H 3.60" magazine...those mags are getting harder to find tho'.

For simplicity sake, if you can't do the work yourself, I would buy a Savage magnum, order a McGowen prefit Savage barrel in 500 AR from McGowen, swap barrels and have a 50 cal for around $600.  For about $400 more PacNor has .585 and .620 cal barrels they will prefit and chamber for you and you'd have a REALLY BIG cannon to play with.

For cheap and fun go with the NEF 20 Ga and have the equal of the 600 3" Nitro...for cheap and fun in a bolt gun go with a Savage 110 action and a "regular" brass case and do the same thing... or go with the 220, stay with the 3" 20 ga chamber and still get more slap at both ends than most people want ...lots of ways to get down the road.

Luck