Shortening a Winchester Model 100?

70m4h4wk

70m4h4wk

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I was recently given a Winchester model 100. It's in rough shape, missing a few pieces. Looks like it might have been a mish-mash of parts from other guns to begin with. The barrel is in need of a new crown, and I was wondering if it might be worth shortening the barrel at the same time.

Has anyone tried this successfully? I was thinking of chopping it to 18.6 inches. I know the carbine was offered with a 19 inch barrel but I can't find any pictures comparing the gas system length of the rifle vs the carbine, and I don't want to end up with a non-functional gun because I chopped the barrel too short.

I'm not concerned about preserving collector value, since there's no original finish left on the gun or the stock. looks like someone shortened the butt themselves quite poorly. I'm just trying to salvage something useful out of this box of parts.

Any idea how short I can go on the barrel?
 
Does it work now? Some 100s were problematic. If it isn't smooth functioning before alterations, it isn't likely going to get any better.
 
captonion said:
19'' to me safe..
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That's the same length as the carbine. Do you know if the gas system is the same length on both?

tiriaq said:
Does it work now? Some 100s were problematic. If it isn't smooth functioning before alterations, it isn't likely going to get any better.
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The function check went well. Everything seems to fit properly and no issues with the action. It seems just as good as the collectable one I have. I haven't had a chance to test fire it yet.
 
Well since you have two M100's take them apart lay them side buy side and compare. I doubt very much you will find any meaningful differences. Why Winchester made the carbine with a 19" barrel over and 18" is not common knowledge. There may indeed be some technical reason to do with gas pressure, but that is usually govern buy the size of the gas ports as opposed to barrel length. Since you planned on shortening the barrel at 18.5, chop it at 19" as the 1/2" is not readily notable.

Since the vast majority of M-100's were cambered for .308 I can not see why the fella in post #3 is determined will have to reload as 308 ammo is most readily available.
 
mrgoat said:
Since the vast majority of M-100's were cambered for .308 I can not see why the fella in post #3 is determined will have to reload as 308 ammo is most readily available.
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I have read that if the pressure at the gas piston port is too High, it is prone to ripping the rims off brass, in the 100

A buddy had one and my experience with it was when he called me over and when he took it apart and he could not get it back together
 
Before you bastardize a good 100 rifle, I have for your consideration a 100 barreled action that has a slight bulge at the end. Ideal candidate for a cut down.
As for ripping brass apart, it was generally from cases getting stuck in a dirty chamber. Cleaning the chamber correctly, often solves this issue.
 
mrgoat said:
Well since you have two M100's take them apart lay them side buy side and compare. I doubt very much you will find any meaningful differences. Why Winchester made the carbine with a 19" barrel over and 18" is not common knowledge. There may indeed be some technical reason to do with gas pressure, but that is usually govern buy the size of the gas ports as opposed to barrel length. Since you planned on shortening the barrel at 18.5, chop it at 19" as the 1/2" is not readily notable.

Since the vast majority of M-100's were cambered for .308 I can not see why the fella in post #3 is determined will have to reload as 308 ammo is most readily available.
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I don't have a carbine though, I have two rifles. That's the problem.

just having some fun said:
I have read that if the pressure at the gas piston port is too High, it is prone to ripping the rims off brass, in the 100

A buddy had one and my experience with it was when he called me over and when he took it apart and he could not get it back together
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I have not experienced this, but I only shoot steel and high quality hunting ammo.

m1008 said:
Full auto recall/repair done?
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In progress, just waiting on parts to arrive.

gunrunner100 said:
Before you bastardize a good 100 rifle, I have for your consideration a 100 barreled action that has a slight bulge at the end. Ideal candidate for a cut down.
As for ripping brass apart, it was generally from cases getting stuck in a dirty chamber. Cleaning the chamber correctly, often solves this issue.
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"Good" is not a word I would use to describe this gun. I also couldn't afford shipping, let alone give you anything for it.
 
I have chopped a few rifles and crowned myself. All of them are still moa or better rifles.
18.5" is minimum you can go before the gun becomes prohib so I would say 18.75" is best just to be absolutely certain your not making it a prohib... measurements are taken from bolt face to muzzle....make sure you are careful not to go under 18.5"!!
One of the best methods I have used is using a lee case cutter and case length gauge. What I have done is cut with hack saw just proud of your overall length. I select a case length guide that is either slightly too large ( chucking in a drill and slowly turn it down using a file until it's a tight fit in your bore. OR a slightly undersized gauge and add tape or even aluminum shim in the bore make it a tight fit. The cutter head will now face your bore 90deg to the bore. The hardened cutter mills barrel steel quite effectively. I then use a round carbide cutter in a tap handle to cut my crown ( the round cutter ensures concentric crown referenced off the bore and will always be even) and use lapping compound to lap it to mirror finish. Break the outside sharp edge of the barrel with a file and Emery cloth and polish it up and blue the whole deal.. this system works like a hot dam.
 
Grouse Man said:
Just curious, why do you want to shorten it?
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For fun. It's not in great shape, definitely no collector value. I've already got a nice one. If I can bring some life back to this one and turn it into a short, handy bush rifle it'll get quite a bit of use. It's also a good opportunity to practice all of the skill involved.

obsessed1b said:
I have chopped a few rifles and crowned myself. All of them are still moa or better rifles.
18.5" is minimum you can go before the gun becomes prohib so I would say 18.75" is best just to be absolutely certain your not making it a prohib... measurements are taken from bolt face to muzzle....make sure you are careful not to go under 18.5"!!
One of the best methods I have used is using a lee case cutter and case length gauge. What I have done is cut with hack saw just proud of your overall length. I select a case length guide that is either slightly too large ( chucking in a drill and slowly turn it down using a file until it's a tight fit in your bore. OR a slightly undersized gauge and add tape or even aluminum shim in the bore make it a tight fit. The cutter head will now face your bore 90deg to the bore. The hardened cutter mills barrel steel quite effectively. I then use a round carbide cutter in a tap handle to cut my crown ( the round cutter ensures concentric crown referenced off the bore and will always be even) and use lapping compound to lap it to mirror finish. Break the outside sharp edge of the barrel with a file and Emery cloth and polish it up and blue the whole deal.. this system works like a hot dam.
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Thanks for the tips! I think I have all the tools I need, if not one of my buddies should have them.
 
I may be overthink this, but nothing after where the gas system connection should have an impact on the cycling action.
I'm a machinist and would do this for you if we weren't on opposite coasts.
 
Jahnj0584 said:
I may be overthink this, but nothing after where the gas system connection should have an impact on the cycling action.
I'm a machinist and would do this for you if we weren't on opposite coasts.
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Dwell time is the time where the bullet is past the gas block, so gasses are travelling into the gas port, but before it has left the barrel, so it is maintaining forward obturation. Insufficient dwell time would make it short stroke. That's why I didn't want to cut the barrel too short.
 
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