What's new
What's new

Eliminate bulge in barrel???

heckinohio

Aluminum
Joined
Aug 25, 2009
Location
Ohio, USA
Gents, some years ago, Donna was shooting a bipod 9mm machine gun and got a squib rnd, which was followed immediately by a good one. Resulting collision made a noticeable bulge in the matching numbered barrel. This is a super scarce gun. I have no idea how I came up with the barrel I now have in the gun..........however, I would really like to salvage the original numbered barrel, saving the original tool marks on the outside..

Asking the impossible...????

I havnt made any headway on the Jap 99 bolt yet, machine guy had a bit of a fire outside and is trying to get that squared away.

PJH
 
Quite easy...make up a pair of swage blocks ,and reduce the bulge until its of exterior uniform dimensions.....this process is done all the time with shotguns and some plastic auto pistols that are prone to bulges that affect operation. .....Incidentally,off the hobby guns,a person here has perfected the removal of exterior non conformities in motorcycle fork stantions ......very expensive repairs normally requiring replacement ,saving insurance repairers much dollars.
 
JohnK.........would my machinist know what swage blocks are? I dont.... And, would a interior rod of just barely tap in thightness be a good idea??

GGaskill...... I have no idea, but suspect I could get a close gestimate by measuring the OD close to the bulge and deducting the bullet OD from that and dividing by 2???

PJH
 
I have no idea, but suspect I could get a close gestimate by measuring the OD close to the bulge and deducting the bullet OD from that and dividing by 2?

That's how I would do it. Although measure on either side of the bulge, not the bulge itself.
 
Forget the rod..it will defeat the process,and may be jammed ....you will have to over swage the barrel,as it will spring back some ......forget the bore entirely,whatever will be ,is......just get the OD nice and regular......While back I restored the barrel of a 1878 made gun that had the muzzle squashed on surplus.....Amazing how many thou the thin 1878 steel would spring back.....when I took on the job,I imagined the barrel would be dead soft...no way ,it was quenched and tempered steel.
 
Gents, some years ago, Donna was shooting a bipod 9mm machine gun and got a squib rnd, which was followed immediately by a good one. Resulting collision made a noticeable bulge in the matching numbered barrel. This is a super scarce gun. I have no idea how I came up with the barrel I now have in the gun..........however, I would really like to salvage the original numbered barrel, saving the original tool marks on the outside..

Asking the impossible...????

I havnt made any headway on the Jap 99 bolt yet, machine guy had a bit of a fire outside and is trying to get that squared away.

PJH

If the barrel is straight, then making the swage blocks is pretty easy, you want essentially a hole through a split bar, with a little space to spare. Squeeze it with a decent hydraulic press. Squeeze, rotate the barrel in the block, repeat as required.
If the barrel is tapered, it's a little more complicated, as you will want your block to have the same taper in the hole through it. As the block gets squeezed inwards, you may have to move the block sideways a bit to account for the tapers matching up.

Nothing is impossible, some things are just harder than others! :)

If it came right down to it, some heat may be required. Use a heat preventative paste or similar material, or fill the bore with inert gas to prevent it getting all scabby from the heat.
 
I can make the blocks you need. I repaired a barrel with swage blocks years ago, when I was done you could not tell there was ever an issue. Before I started I Magnafluxed the barrel to inspect for cracks in the bulged area. It was good. I did it with no heat so there was no damage to the finish. PM me if I can help.
 
I've removed bulges from shotguns using an internal mandrill, and it worked perfectly.
Should you need to do this I'll provide details.
But for a rifled bore, and you need to press it back into position using outside clamping blocks.
 
A friend of mine was always trying to develop a light load for 1911 .45ACP pistol for competition target shooting. He bulged the barrel the same way when a light load didn't push the bullet out the barrel and he fired another behind it. I replaced it a few times but he did it so often he asked if I could fix the bulge since the bushing needs to slide over it. I put it in a lathe and used a roller steady rest and "rolled to back to size. Afterward we put the pistol in a Ransome rest, I was surprised to see it grouped as good (under 2" at 50 yards) as it did prior to the bulging. Barrel was Kart target barrel.
 
Did he ever increase his load so they made it out of the barrel reliably? Roller swaging once or twice sounds OK but eventually it will work harden the barrel.
 
Only rolled them one time, new barrels were expensive and time consuming to install. Yes he did bulge the barrel 3 times but we had 3 barrels because every time he bulged a barrel we got a new one. Plus I checked to see what he was doing to reload ammo that didn't get out of the barrel. I had a Dillon Square Deal I never used, new in box and sold it to him. Problem stopped!
 
RE: (Did he ever increase his load so they made it out of the barrel reliably?)
With the odd bad primer, one can never be sure not to have a squib.
I Had to re-barrel my SW 38 because if that. It was a tractor gun for a bear scare.and frequent oiling must/may have gotten into a bullet(?).
Back in the day with shooting militarys we would listen for the dull report, can't do that with a machine gun.

If moonlight machine cant do it , it seems a really good CNC guy could match all the logo/markings on/with a new barrel.​

 
Last edited:
I ve seen pics of more than six bullets in a revolver barrel.....reloaded and kept firing until a bullet jammed the chamber from rotation.....Ive personally seen many ,possibly 10 bullets in a 22 rifle......the owner didnt like the quote for removal ,so took the gun home and melted the bullets out on a gas barbecue......he made a point of bringing it back to show me how to do it .......a common cause of a small bulge in the army 303s was a neck would detach from a crimped brass blank cartridge,next time a bullet was fired,the brass neck would be stamped into the bore,leaving a plainly seen smooth spot ,but the outside with an very slight bulge,almost unnoticable.
 








 
Back
Top