Chambering Problem

[ken98k]

This is a new one to me so I hope someone has a suggestion.

Here's the story-

 

I'm finally getting around to chambering my Siamese 45-70.

The barrel is an ER Shaw that I bought "fully chambered".

The threaded shank was too long so I shortened it. I don't remember how much, maybe a 1/16" or so.

Next I relieved the last thread next to the shoulder.

After assembling the barrel to the receiver, I determined where the extractor relief cut should be, then I removed the barrel and made the cut and reassembled.

 

Now comes the problem. My PTG finish reamer goes in then binds up about 3/8" short of where it needs to go.

It is not cutting at all however,

a. A go gage will drop into the chamber to the rim.

b. A loaded cartridge will drop into the chamber all the way to the rim.

c. The piloted end of the reamer will fit into the muzzle end of the barrel.

d. When I look into the chamber it looks much like my T/C 45-70 chamber with a distinct shoulder for the cartridge mouth. (like a shotgun)

e. The reamer fits easily into the contender chamber.

 

 

[z1r]

This is a new one to me so I hope someone has a suggestion.

Here's the story-

 

I'm finally getting around to chambering my Siamese 45-70.

The barrel is an ER Shaw that I bought "fully chambered".

The threaded shank was too long so I shortened it. I don't remember how much, maybe a 1/16" or so.

Next I relieved the last thread next to the shoulder.

After assembling the barrel to the receiver, I determined where the extractor relief cut should be, then I removed the barrel and made the cut and reassembled.

 

Now comes the problem. My PTG finish reamer goes in then binds up about 3/8" short of where it needs to go.

It is not cutting at all however,

a. A go gage will drop into the chamber to the rim.

b. A loaded cartridge will drop into the chamber all the way to the rim.

c. The piloted end of the reamer will fit into the muzzle end of the barrel.

d. When I look into the chamber it looks much like my T/C 45-70 chamber with a distinct shoulder for the cartridge mouth. (like a shotgun)

e. The reamer fits easily into the contender chamber.

 

There is a good chance the pilot is too big for the chamber end of the barrel. It is not uncommon for each end of the barrel to be slightly different in size.

 

It happened to me before.

 

[ken98k]

There is a good chance the pilot is too big for the chamber end of the barrel. It is not uncommon for each end of the barrel to be slightly different in size.

 

It happened to me before.

 

I think you're right. I painted the pilot with layout dye and tried it again. Only a small section at the tip of the pilot was touched.

I guess I'll try calling PTG on monday to see if they'll grind it down a little.

Thanks,

Kenny

[z1r]

Better yet, ask them to convert it to a removable pilot reamer but either will work. Either way, Dave will probably ask you what diameter you want. Do you have any pin gages to determine what the bore really is?

 

Another thought, is tere any chance that there is a burr or two left over from the chambering job? Something to check that won't cost you anything.

[sonic1]

z1r how does the 45-70 head space ?..if the go gauge all ready drops in and also a loaded cartridge.. i"m a little fuzzy about

this..i:ve never worked with rimmed cartridges

[z1r]

z1r how does the 45-70 head space ?..if the go gauge all ready drops in and also a loaded cartridge.. i"m a little fuzzy about

this..i:ve never worked with rimmed cartridges

 

All rimmed cartridges are supposed to headspace off the rim.

 

The reamer going in or not really has nothing to do with headspace. From the description It is hard to tell what the headspace really is. It could be right and the reamer could still not fit due to the pilot.

 

The following is for illustration purposes only, (I did not dig out my Siamese and measure things):

 

Some rimmed cartridges will have the rim countersunk and some not. This all depends on the breeching system employed. A mauser, not necessarily a siamese, will nominally have about .110" space between the breech and the boltface. While a .45-70 rim is something like .060" thick. This means you would have to use a breech like those used in the safety breeched mausers. The breech would need to protrude beyond the inner "C" ring. Make sense?

[ken98k]

I really did a bubba job now.

I got called out last night on a no-heat and didn't get home till 11:30 so I was a little P-Oed. I went out to my shop and decided to give this thing one more try. It took a good deal of effort to turn and push in on the reamer and as a result went too far because I couldn't feel the reamer cutting as is normally the case.

 

Sonic,

This is how I set this action up.

The receiver had a lip at the front shoulder just like a k-kale, which I removed. I believe that is why the ER Shaw threaded shank had to be shortened.

I made the breech end touch the inner c-ring as it would with a normal 98. Since the rim around the boltface is even with the forward face of the c-ring I needed to make a relief cut for the extractor.

There was a slight recess for the cartridge rim on the Shaw barrel. Re-cutting that recess is where I ran into the problem with the tight reamer.

It seems that when I shortened the thread barrel shank I merely removed the rim recess without affecting the actual chamber.

Hindsight tells me that I should have head spaced before making the extractor cut, but having never done or even seen one of these before---.

 

I guess what I’m going to do next is completely remove the threaded shank and start all over again.

 

If I didn’t have so much time and money invested in this rifle, I’d scrap it, but I’m determined to see it through.

This is my 4th project since getting this addiction in 2003 and out of the 30 plus Mausers I own, I still haven’t even done a standard 98 yet!

 

[donmarkey]

Can't you just set back the shoulder than ream again? With a proper pilot this time. Some people think I'm nut but this is why I put projects away for a few months, before I destroy them by rushing through something. I have a few receivers sitting on my bench to remind me this.

-Don

[riceone]

Maybe I came in the wrong door. But for my information what is the problem. Gauge goes is so does the cartridge. Why are you using the reamer. I thought in long chambered barrels like you describe you did not need a reamer. Not being critical, trying to understand for my own benefit. Thanks riceone.

[ken98k]

Maybe I came in the wrong door. But for my information what is the problem. Gauge goes is so does the cartridge. Why are you using the reamer. I thought in long chambered barrels like you describe you did not need a reamer. Not being critical, trying to understand for my own benefit. Thanks riceone.

 

I needed the reamer because I shortened the chamber end of the barrel.

If I had not removed the k-kale style lip from the front of the receiver the barrel would probably have worked and I would have saved $150.00 for the cost of the reamer and gages.

[z1r]

I needed the reamer I shortened the chamber end of the barrel.

If I had not removed the k-kale style lip from the front of the receiver the barrel would probably have worked and I would have saved $150.00 for the cost of the reamer and gages.

 

If you have to setback the barrel and rethread maybe the reamer will fit. It's possible. Maybe try it before you send it back off for fixing.

 

Definitely set the headspace first, then cut the extractor slot.

 

Funny thing about hindsight, it always kicks in when it's too late.

 

Don't worry, you'll get er done!

 

I've decided to do my Siamese in 7.62x54R. Just in case I ever go hunting internationally where the .30-06 isn't as available. That's my excuse anyway, lol.

 

[riceone]

Mauser, I have three of the rifles, two have been converted to the later cartridge, 8x56 and one in original chambering. I beleive 8x56 brass is sold, I know dies are. riceone.

[ken98k]

If you have to setback the barrel and rethread maybe the reamer will fit. It's possible. Maybe try it before you send it back off for fixing.

 

Definitely set the headspace first, then cut the extractor slot.

 

Funny thing about hindsight, it always kicks in when it's too late.

 

Don't worry, you'll get er done!

 

I've decided to do my Siamese in 7.62x54R. Just in case I ever go hunting internationally where the .30-06 isn't as available. That's my excuse anyway, lol.

 

I think the 7.62X54R will probably feed as well as the original chambering. Wish I had gone that route, but once I get started on an idea-

[roscoedoh]

I think the 7.62X54R will probably feed as well as the original chambering. Wish I had gone that route, but once I get started on an idea-

 

Well then the only solution to your conundrum there is to get another Siamese and build a 7.62x54r. Ya know you want to anyway!

 

[ken98k]

I finally got a few minutes to work on the siamese today.

I re-faced the breech end of the barrel and set the shoulder back and then discovered the bolt would close on the no-go gage.

There does not appear to be any setback oi the recoil lud area.

I guess the next step will be to make a tool to take a few thousands off the c-ring so the barrel can seat closer to the bolt face.

[gun nutty]

Can't you just have a step on the barrel-face that's the inner diameter of the C-ring? The end result will be the same, and you'll need no special tooling.

 

[ken98k]

Can't you just have a step on the barrel-face that's the inner diameter of the C-ring? The end result will be the same, and you'll need no special tooling.

 

You're right.

I'm going to try that before working on the inner torque shoulder.

[z1r]

You're right.

I'm going to try that before working on the inner torque shoulder.

 

Are you countersinking the rim?

[gun nutty]

Are you countersinking the rim?

Can you coutersink it? Would there be an advantage?

 

Is the Siamese 98 bolt face completely smooth?

 

I was talking about an "outty" not an "inny".

 

[ken98k]

Are you countersinking the rim?

 

{The following is for illustration purposes only, (I did not dig out my Siamese and measure things):

 

Some rimmed cartridges will have the rim countersunk and some not. This all depends on the breeching system employed. A mauser, not necessarily a siamese, will nominally have about .110" space between the breech and the boltface. While a .45-70 rim is something like .060" thick. This means you would have to use a breech like those used in the safety breeched mausers. The breech would need to protrude beyond the inner "C" ring. Make sense? }

 

I need to try putting the breach as close as possible to the boltface.

Either by a yugo type extention or removing some metal from the inner torque ring.

[z1r]

Why do I have a sneaking suspicion that I wrote that? If I did I should have added: if you want to fully enclose the case head.

 

On my Siamese here in front of me, the boltface protrudes beyond the inner "c" ring. I don't have the benefit of an original siamese barrel to see how it was handled. I haven't taken any measurements as I only just dug up my action.

 

It seems from the way mine looks that you would need both a counterbore and extractor slot. Are you using the original bolt or a k98?

[ken98k]

Why do I have a sneaking suspicion that I wrote that? If I did I should have added: if you want to fully enclose the case head.

 

On my Siamese here in front of me, the boltface protrudes beyond the inner "c" ring. I don't have the benefit of an original siamese barrel to see how it was handled. I haven't taken any measurements as I only just dug up my action.

 

It seems from the way mine looks that you would need both a counterbore and extractor slot. Are you using the original bolt or a k98?

 

Yup, you wrote that!

The bolt is not original to this receiver, but it is a Siamese bolt. I 'wish' the bolt extended past the c-ring but is just shy of it.

[z1r]

Interesting. Wait, since your's is a .45-70 and mine is original, has the semi-circular guide been removed from the bolt? The one that surrounds the boltface? That may explain why mine protrudes and your's doesn't. My boltface would not protrude but the guide does.

 

Anyway, how much cartridge protrudes or rather what is the difference in measurements of the receiver face to boltface vs the receiver face to "C" ring? Mine is rather short, certainly shorter than the standard 98 dimension.

[ken98k]

Interesting. Wait, since your's is a .45-70 and mine is original, has the semi-circular guide been removed from the bolt? The one that surrounds the boltface? That may explain why mine protrudes and your's doesn't. My boltface would not protrude but the guide does.

 

Anyway, how much cartridge protrudes or rather what is the difference in measurements of the receiver face to boltface vs the receiver face to "C" ring? Mine is rather short, certainly shorter than the standard 98 dimension.

 

I'll get some measurements tomorrow or saturday. I've been putting in a lot of ot lately and have only had a few minutes here a there to work on it.

[machinist1]

Kernak2, Did you ever find a solution to your 45/70 project? I am doing a 45/70 on a Siamese action too. I have the reamer but still need headspace guages. If you would like to sell your gauges when you are done let me know. Have a happy Thanksgiving.

Bob