What can I rechamber my gun to?

[rcmodel]

say a 7mm Mag the new 375 Ruger. Over all cartridge length is very close and should work but what about pressure?

Pressure would not be a problem with any of the belted Magnum caliber actions.
Any action that started out as any belted mag caliber would be strong enough for any of the new "un-belted mag" calibers.

But muzzle dia. of the 7mm Mag barrel might influence whether or not it could be re-bored & rifled to .375 caliber and still have enough metal left.


rcmodel

 

[MikeHaas]

I assure you, the price for cutting a new chamber does NOT include ANYTHING to do with the bore. Mr. Keenan is quite correct.

Only on a gunsmith's invoice - that's the only place these procedures might be itemized separately.

Any one here ever deliver a barrel to a customer that you rechambered to a cartridge with a larger diameter bore but did NOT rebore it? Mr. Keenan? Mr. SigfanUSAF? If so, that's a unique service you provide, I think. Pray tell, how DOES that work for your gunsmithing business?

I for one, have never, not once, not even a little bit, heard some one use the phrase "I once had a gun rechambered and rebored to..." because 'and rebored' isn't necessary. If it was needed, it was done, otherwise the job wasn't finished and you have rendered your customer's barrel not only unusable, but incredibly unsafe. Not a good time to reassemble gun, y'know? Necessary reboring is a separate process, but an integral part of a re-chambering project. This is such a basic tenant that those who would argue otherwise are simply using semantics to be agrumentative, which is a simple waste of time. Mine anyway.

I asked for constructive comments and have received some good ones (all will be noted) - sincere thanks to those that have provided them. Also, some of the discussion here, such as pressure aspects of different actions are exactly the kind of discussion I'd hoped my Re-Chambering Guide would lead to - the logical next step from the Guide's list iof candidates. A productive thread, despite those that endorse the creation of plugged barrels.

Mike

 

[SigfanUSAF]

Mike Haas,

I guess what I'm wondering is how is it your chart says I can rechamber/rebore my 8x57 to .475 Wildey Magnum? I should think my K98 barrel walls would be getting towards shotgun wall thicknesses towards the third step.

Cost wise, would it not be cheaper/safer to buy a blank in your desired bore diameter, contour it, cut a chamber and thread to suite, than to bore a larger hole in your barrel and have new rifling cut?


To add:

despite those that endorse the creation of plugged barrels.

I believe your guide has some uses, however, your comments in the above post were a little less than THR.

I asked for constructive comments and have received some good ones

How is my noting there is a major difference between re-chambering and re-boring not a constructive addition to this thread?

Necessary reboring is a separate process, but an integral part of a re-chambering project.

There are numerous circumstances where the bore/groove diameter is identical during a caliber changeover, and re-chambering is all that is needed.

 

[MikeHaas]

Adding over all case length might help as to what will fit the existing magazine.

Unfortunately, not every round in my database has the OAL data entered because many case diagrams do not include this info. But all have case length entered, so that's the length paramter most reliable. As you see, you can enter the value for the program to use for how much more useable length your action has, so the small distinction becomes mute I think.

Also strength IE pressures, say a 7mm Mag the new 375 Ruger. Over all cartridge length is very close and should work but what about pressure?

Pressure is a difficult parameter to carry across all cartridges because so few wildcat developers/reloaders have access to any type of chamber pressure transducer. How many here do? (Not I)

And again, the program isn't concerned with action specifics other than length and only to filter out rounds that are likely too long. If you want to persue a conversion AmmoGuide lists, you would consult with your gunsmith (as always) and he/she will tell you if it's possible with your gun and the rounds.

You see, I have no database of characteristics of all maufacturer's actions available (notice the program doesn't ask for what kind of action you have) and that is is NOT what the program is designed to look at - WAAAY outside of the scope. It is designed only to look at cartridge dimensions - further refinement of a selection is left as an excercise for the user (as it always is). The Guide only helps with the first step - figuring out which rounds are PHYSICAL candidates, not the last step - the actual selection of a cartridge.

The cases are almost the same dimensions with the exception of a much larger bore

I was thinking more along the lines of a rebarrel than rechamber which would be IMO a good option for your program.

Well, from a dimensional aspect, a rebarrel is obviously much less restrictive than a rechamber because virtually any cartridge of the same rim construction, even those of smaller bore, are candidates. That should be an easy enhancement, I'll put it on the "to do" list. If you don't see that option appear within a month or so, contact me over AmmoGuide.com. Thanks - good suggestion.

This program has it's flaws perhaps but is something new and I for one appreciate it and would like to see even more information, programs, and ideas along these lines.

The ability to do side by side comparisons is good.

Thanks Mike

You're welcome, same at ya. Your comments are among the best.

Mike

 

[SigfanUSAF]

To back up my point, here is an excerpt from Z-Hat Custom Rifles, simply because that was the first site that popped up in a Yahoo search for "rechambering cost"....
http://www.z-hat.com/rechamber.htm

A plain rechamber is $105

Cost to rebore your barrel, $375

At $375 for reboring it's well above the cost of most aftermarket barrels available in numerous calibers for most common mil-surp and sporting rifles.

 

[jimmyraythomason]

7x57 Mauser to .280 Remington.

According to the guide, this conversion is not possible because the .280 is too long. I have tried the .280 cartridge in my 1912 Mexican Mauser and it works fine. I put 5 rounds in the magazine and worked them through the action. Every round fed flawlessly(it just couldn't chamber). This was with the original magazine but I have a lengthened commercial magazine. This rifle has a new heavy commercial barrel,so why can't I rechamber to .280? The cartridge length arguement doesn't fly.

 

[kellylicon]

the charts on ammoguide have given me the idea to run a low pressure 405 winchester round through my 98 springfield. close pressures, close overall length and some good loads make this seem rather easy. a barrel from brownells and this should be an easy one. does anyone out there mess with the 98 springfield action? thanks

 

[eliphalet]

7x57 Mauser to .280 Remington
The cartridge length arguement doesn't fly

the responce was,

Sorry, but based on your settings, you cannot re-chamber your 7x57R Mauser firearm to .280 Remington because the case of the .280 Remington is too narrow at the top of shoulder.

Go back and look the numbers over again.

 

[Jim Watson]

kellylicon,

Will the Krag's smooth but complicated and finicky magazine handle .405 Win? I don't know, but you should before you start in on it.

 

[kellylicon]

jim watson,
the forcing finger and disconnect both feed and work with the 405. due to bullet profile the forward mouth of the magazine channel needs to be shaped slightly for the 405's bullet. pressure is close with a 4000 cup difference between factory loads of 30-40 and the 405.

 

[Jim Watson]

Sounds like an interesting approach to getting kicked if you have a Krag to tinker with. All I know about that is what I read in DeHaas about things like lapping in the locking lug so the safety lug bears, etc.

 

[jimmyraythomason]

x57 to .280Remington

This is a different response than the first one I got. The first response said that the .280 cartidge was too LONG for my action and included no comparison drawing(since been added). The second response( the one eliphalet cited) makes perfect sense and is acceptable. FWIW, I do not want to change my 7x57 to .280Rem. just wanted to see if it was possible. Thanks.http://ammoguide.com/cgi-bin/aichamber.cgi

 

[MikeHaas]

eliphalet said: ...I was thinking more along the lines of a rebarrel than rechamber which would be IMO a good option for your program...

I replied: Well, from a dimensional aspect, a rebarrel is obviously much less restrictive than a rechamber because virtually any cartridge of the same rim construction, even those of smaller bore, are candidates. That should be an easy enhancement, I'll put it on the "to do" list. If you don't see that option appear within a month or so, contact me over AmmoGuide.com. Thanks - good suggestion.

Added. Main screen now looks like:

http://ammoguide.com/cgi-bin/aichamber.cgi

Also, on further testing, the tool has uncovered some anomolies in some case dimensions. For example, it said a .280 Rem could not be rechambered to a .280 Ackley Improved. The problem wasn't the Guide, it was the dimensions of the Ackley round in the database were not correct (too small at the top of shoulder.) I've corrected them and since gone through and verified most other Ackley dimensions.

Thanks again for the (truly) constructive comments!

Mike

 

[MikeHaas]

Assuming your current chambering is a .416 Barrett - here's a simple example illustrating the use of the Guide...

With these options...
- Re-Chamber (not rebarrel)
- No boltface/extractor modifications
- keep same case length limitation

...clicking the "List All Candidates" button, the Guide reports "No candidates"

But if we remove the action length limit - select "Disregard" for action length, the Guide reports...

1. .510 DTC
2. .50 BMG

(all longer rounds that can be formed from a .416 Barrett chamber that have the same rim dimensions.)

Now change from "Re-Chamber" to "Re-Barrel" and the Guide returns another candidate...

1. .375-50 BMG
2. .510 DTC
3. .50 BMG

The .375-50 BMG wildcat cannot be formed from a .416 Barrett chamber because the bore is smaller (no metal where needed in the Barrett chamber/barrel). But it *IS* a valid candidate for rebarreling, having the same rim characteristics.

This example is pretty clear because there aren't many rounds that have that big .804" rim. But when dealing with a more common rim size (like .47"), the Guide can help identify candidates you may have never thought of.

Mike

 

[MikeHaas]

7x57 Mauser to .280 Remington...
According to the guide, this conversion is not possible because the .280 is too long. I have tried the .280 cartridge in my 1912 Mexican Mauser and it works fine. I put 5 rounds in the magazine and worked them through the action. Every round fed flawlessly(it just couldn't chamber). This was with the original magazine but I have a lengthened commercial magazine. This rifle has a new heavy commercial barrel,so why can't I rechamber to .280? The cartridge length arguement doesn't fly.

In response to the Guide question "Can your action/magazine support a longer cartridge?", you selected this answer... "No - Keep same max case length (or shorter) as original round". the .280 Remington is much longer than the Mauser round and the first thing you need to do is tell the tool your action can handle that long a round.

However, there may still be other dimensional problems with this conversion (which is why the tool displays both case diagrams) - read my next post.

Mike

 

[MikeHaas]

Sorry, but based on your settings, you cannot re-chamber your 7x57R Mauser firearm to .280 Remington because the case of the .280 Remington is too narrow at the top of shoulder.

Yes, this is what I was getting to...

Notice the neck diameter (OD) of the 7mm is .324" and the .280 says .315". The diagrams also show the top of the 7mm neck will form the base of the .280's neck.

Now, this may not be enough difference to prevent a successful conversion - as the Guide warns, always involve a competent gunsmith - but the Guide sees that the neck may be loose there and is flagging it to you.

Mike

 

[jimmyraythomason]

.280Rem in 7x57 magazine

I accept the fact that the .280 is too narrow to rechamber a 7x57 for. BUT I checked the site at "no length extention,at.25" extention and finally at .50" extention. Only the .50 ext. query yeilded the "too narrow" result. No lengthening and lengthening by .250 got a "too long" result. The fact remains,however, that the .280 works through my 7x57 UNMODIFIED magazine and action flawlessly making the "too long" response inaccurate.

 

[eliphalet]

I think the program is right Jimmy as the 7X57 is .305 shorter than the .280 Remington so checking .250 wouldn't show, but your asking the program to think and reason and not just crunch numbers.
Also your correct in the OAL working I do believe.
It is so close a guy would have to check farther than i quickly did, but if the .003 wider at the base of the 7X57 wasn't to much to cause case splits or problems, it looks to me like a rechamber might just work when you compare the OAL of the cases and the width or diameter in relation to the case length at the base and top of the shoulders.
It could undoubtedly be explained better than I just did too using my layman's terms and was done quickly also.
I guess like stated "ask a competent gunsmith"
I still like it faults or not.

 

[jimmyraythomason]

For me it is a moot point. When I had the rifle rebarreled I deliberately chose the 7x57mm over the .280 Rem. I could just as easily have chosen either. I think the guide is going to be a great resource for rifle builders once the "bugs" are worked out.

 

[MikeHaas]

I'll be looking into all the reports and reply here soon, and thanks all for taking the time.

Quick update: Just added another Stephen P. Gibbons suggestion - one that may reflect on some of the earlier questions raised here regarding reboring.

It's another "Rechambering conversion option"...

...one where you do not want to rebore.

For example, I just told the tool to:
- "List All Candidates" for
- "ReChambering, no reboring" a
- ".30-06 Springfield"
- with no boltface or extractor modification
- disregarding case/action length limitations

And it reported...

1. .30 Gibbs - http://ammoguide.com/?catid=444
2. .30-06 Ackley Improved - http://ammoguide.com/?catid=255
3. .300 Howell - http://ammoguide.com/?catid=586

Seems about right. (BTW, this is how I've tried to make AmmoGuide.com useful to shooters - by listening to what shooters want. Enjoy.)

Mike

 

[MikeHaas]

I accept the fact that the .280 is too narrow to rechamber a 7x57 for. BUT I checked the site at "no length extention,at.25" extention and finally at .50" extention. Only the .50 ext. query yeilded the "too narrow" result. No lengthening and lengthening by .250 got a "too long" result. The fact remains,however, that the .280 works through my 7x57 UNMODIFIED magazine and action flawlessly making the "too long" response inaccurate...

No - remember, the tool has no idea what your action can handle. It has no idea what your action is. It can only go by the length of your current cartridge case - that of a 7x57mm.

When the tool shows you the case diagrams for the 7x57mm and the .280 Rem, look at the case lengths... The 7x57 is 2.235 inches, the .280 Rem is 2.540 inches.

The difference is .305 inches.

That's why it gave you a length error when you tried .25 inches, but gave the expected error message at .50 inches. If you try .306 inches, you will see it works just like .50 inches - no length error is displayed.

So the tool is correct. Again, I'm looking for bugs and would be glad to have something to go fix, this just isn't one. I hope my explanation is clearer than mud.

Mike

 

[MikeHaas]

I think the program is right Jimmy as the 7X57 is .305 shorter than the .280 Remington so checking .250 wouldn't show

Exactly!

Also your correct in the OAL working I do believe.
It is so close a guy would have to check farther

That's EXACTLY what the tool is designed to do... show possibilities... show you "Hey, this might work..." so that you, and possibly your gunsmith, can look into it further, while filtering out all the "No Way" rounds. It would take MANY HOURS to manually compare all the dimensions the tool does for you in less than a minute.

It's a research tool. And I think a pretty darn smart one. What else do you know that actually analyzes and compares the SHAPES of cartridge cases? And based on YOUR control.

Anyway, hope it helps someone. Sounds like it may already have with a .405 suggestion. Price is right, eh?

Any other issues, glad to address 'em. This thread has been very helpful - either providing useful suggestions, revealing problems or verifying the tool correct.

Mike

 

[MikeHaas]

As a final enhancement (for now), the Guide no longer stops on the first problem and now prints ALL issues it finds with a requested conversion.

For example, checking if a .308 Win. can be converted to .35 Whelen in a .308-length action *AND* without reboring displays these errors...
---
Sorry, but based on your settings, you cannot ReChamber your .308 Winchester (7.62mm NATO) firearm to .35 Whelen because the bore diameter of the .35 Whelen is not the same as the .308 Winchester (7.62mm NATO) (ReBoring is necessary).

Also, the .35 Whelen case is too long for your action.
---
It previously would only display the first error. Of course, it still displays the case diagrams for both rounds, side-by-side.

http://ammoguide.com/cgi-bin/aichamber.cgi
(On the login screen, just Press 'Enter as DEMO' if you don't have an account. The Guide will still work for you.)

Mike

 

[AnthonyC.]

Ummmm ok it said that I could rechamber my .22 rifle in to a .577 Tyrannosaur
.....I WISH

 

[Jim Watson]

Best I can tell, the main reason you cannot rechamber (+ rebore) a .308 to .35 Whelen is that the greater taper of the Whelen ('06) means it will not "clean up" the .308 chamber. Looks like about a .007" step left at the old .308 shoulder location. Doesn't sound like much but it would stick out on a fired case.