45-90 drawings....HELP !!

[Big Cat]

Hi Guys,
Does anybody has a detailed 45-90 Sharps chamber dimension draws ?
Any help is very welcomed !!!

Cheers....

Big Cat :-|:-|

[nicholst55]

I'd give the folks at PTG a shout; they list several different reamers for the BPCR cartridges, and could probably help.

[Tom Myers]

These are sketches of the dimensions that I have on file for a Winchester Browning chamber and also a supposedly tight Sharps match chamber that someone sent me. I can't vouch for the accuracy as I didn't personaly determine the chamber dimensions.
Perhaps they can give you an idea of what to expect.


http://www.tmtpages.com/LinkSkyImages/forum_images/45-90/45-90_Winchester_Browning~Barrel-250.gif

http://www.tmtpages.com/LinkSkyImages/forum_images/45-90/45-90_Sharps_45-90_Tight_Specs~Barrel.gif

Hope this helps

[montana_charlie]

Does anybody has a detailed 45-90 Sharps chamber dimension draws ?
Are you looking for information on modern-made chambers, or those in antique rifles? There has been an 'evolution' of sorts.

The 'chamber dimensions' (as illustrated in Tom's drawings) will all be about the same, but different manufacturers use varying shapes for the 'throat'.

If you can tell us what you are trying to understand...figure out...or learn about...perhaps we can come up with something specific.

CM

[Big Cat]

Are you looking for information on modern-made chambers, or those in antique rifles? There has been an 'evolution' of sorts.

The 'chamber dimensions' (as illustrated in Tom's drawings) will all be about the same, but different manufacturers use varying shapes for the 'throat'.

If you can tell us what you are trying to understand...figure out...or learn about...perhaps we can come up with something specific.

CM
Hi Montana Charlie,
I am interested in modern made chambers. I got a 45-90 Shiloh Sharps and I would like to have a detailed chamber draw of it.

BC

[montana_charlie]

I got a 45-90 Shiloh Sharps and I would like to have a detailed chamber draw of it.
Ahh! I see...
Since yours is a Shiloh, I presume you have asked the manufacturer for this drawing...and came here when they did not provide one.

Several years ago, back when the Clymer folks still had reamer diagrams posted on their site, I copied two that they offered.
One was identified as the .45/90 Winchester chamber and the other was labeled as a '2.4" Sharps chamber'.

After much reading, I have come to believe it closely approximates the chamber used by Shiloh, but I don't know that for a fact.
It's just that when I read the dimensions guys take from their chamber casts, they always seem to agree with the dimensions in this one...

http://castboolits.gunloads.com/picture.php?albumid=88&pictureid=2237

Of course, the picture doesn't 'look' anything like a chamber. It is just a generic diagram which illustrates the various elements that make up a chamber and throat.
But, the numbers should enable you to create a scale drawing of the chamber this reamer was designed to cut.

Even then, however, you will have an approximation...even if it IS a Shiloh chamber...because you can expect some variation in any pair of barrels.
Some will state that each Shiloh is exactly on spec...and that all are identical.
But, I have sold case stretchers to Shiloh owners who found their chambers to be deeper than expected.

Your best course of action is to make a chamber cast of your rifle.

CM

[Big Cat]

Thank you to everybody !!

Big cat

[Tom Myers]

-----------
Several years ago, back when the Clymer folks still had reamer diagrams posted on their site, I copied two that they offered.
One was identified as the .45/90 Winchester chamber and the other was labeled as a '2.4" Sharps chamber'.
-----------
CM

CM,

I added your Clymer specs to my database and these are the sketches produced with those values.
Trimmed the Case to fit and loaded with a Paul Jones Bullet.
Much easier to visualize and understand the fit with a graphic image.

http://www.tmtpages.com/LinkSkyImages/forum_images/45-90/45-90_Clymer_45-90_2.4_Sharps~Barrel.gif

http://www.tmtpages.com/LinkSkyImages/forum_images/45-90/45-90_Clymer_45-90_2.4_Sharps~Paul_Jones_Mold_458-450-550-big.gif

http://www.tmtpages.com/LinkSkyImages/forum_images/45-90/45-90_Clymer_45-90_2.4_Sharps~Paul_Jones_Mold_458-450-550.gif

[Don McDowell]

Hi Montana Charlie,
I am interested in modern made chambers. I got a 45-90 Shiloh Sharps and I would like to have a detailed chamber draw of it.

BC

You don't need a chamber draw, you need to get a plug of cerrosafe and do a chamber cast then you'll be able to see exactly what the chamber of your rifle is.

[montana_charlie]

CM,

I added your Clymer specs to my database and these are the sketches produced with those values.
Trimmed the Case to fit and loaded with a Paul Jones Bullet.
Much easier to visualize and understand the fit with a graphic image.
Pretty spiffy, Tom. I am jealous of your software.

One thing, though...the rim thickness is too small.
I know what the numbers in the diagram say, but that is specification for the cutter...not the hole it cuts.

The reamer would surely be driven in deep enough to get a rim recess closer to .067" or .070". (I think .070" is 'nominal' and .067" is more typical.)
That little quirk may explain why chambers are often cut deeper than what the owner expects.

If a .067" recess is cut with the reamer in the diagram, the 'K' dimension will result in a chamber a shade over 2.4" deep.
A poorly figured number in the 'K' slot could be responsible for those chambers that run 10 to 50 thousandths too deep.

I once saw a reamer diagram that had 2.4" in that position. It seemed great at first glance, but not after adding the rim recess.

CM

[Big Cat]

Thank you for your draws Tom !

Cheers,
Big Cat

[texasmac]

Tom,

I can definitely tell you the chamber illustration you have for a Winchester/Browning .45-90 is not accurate. I've made chamber casts and taken careful measurements of several Browning .45-90 chambers prior to finishing my book on the Browning's, plus I’ve had several discussions with Browning concerning their chambers. Many of the dimensions you list are close, but the Browning chamber does not have a well defined constant diameter neck. The case body is a constant taper from rim to case mouth, hence no well defined neck. Another dimensional difference is the transition step angle from case to throat, which is 12.75 degrees in an actual Browning chamber versus 45 degrees in your illustration. There are other differences .

Wayne

[Tom Myers]

Tom,

I can definitely tell you the chamber illustration you have for a Winchester/Browning .45-90 is not accurate. I've made chamber casts and taken careful measurements of several Browning .45-90 chambers prior to finishing my book on the Browning's, plus I’ve had several discussions with Browning concerning their chambers. Many of the dimensions you list are close, but the Browning chamber does not have a well defined constant diameter neck. The case body is a constant taper from rim to case mouth, hence no well defined neck. Another dimensional difference is the transition step angle from case to throat, which is 12.75 degrees in an actual Browning chamber versus 45 degrees in your illustration. There are other differences .

Wayne

Wayne,

Thanks for the heads-up on the Browning dimensions. As I mentioned, my notes show that I didn't personally measure the chamber.

If it is not too much trouble, any additional data you could provide would be sincerely appreciated. If you could either post it here or PM me, I could then update my database and display a more accurate dimensional sketch of the Browning chamber.

[Tom Myers]

CM,

Thanks for the Kudo's on the software. If I can ever get ahead of Microsoft Window's changes, I hope to someday be able to distribute all of the Bullet, Case and Chamber drawing software in one package.

Thanks for the information. I noticed the thin rim cut when I first entered the data, but went ahead and entered as it was shown.

I have now re-entered a rim thickness of 0.067", added the difference to the chamber depth and redrew the case to 2.4 then put it all together and updated the images displayed above.


Pretty spiffy, Tom. I am jealous of your software.

One thing, though...the rim thickness is too small.
I know what the numbers in the diagram say, but that is specification for the cutter...not the hole it cuts.

The reamer would surely be driven in deep enough to get a rim recess closer to .067" or .070". (I think .070" is 'nominal' and .067" is more typical.)
That little quirk may explain why chambers are often cut deeper than what the owner expects.

If a .067" recess is cut with the reamer in the diagram, the 'K' dimension will result in a chamber a shade over 2.4" deep.
A poorly figured number in the 'K' slot could be responsible for those chambers that run 10 to 50 thousandths too deep.

I once saw a reamer diagram that had 2.4" in that position. It seemed great at first glance, but not after adding the rim recess.

CM

[texasmac]

Tom,

I retract what I said earlier. I must have been looking at the wrong illustration. Your drawing of the 45-90 Browning/Winchester chamber is right on for the most part. One comment I'd now make concerning your Browning/Winchester specs is the factory official freebore length is 0.150", but the effective freebore length is longer, although not as long as shown in your illustration. As you drawing illustrates, the freebore diameter is larger than the bore diameter. Therefore there's an additional cone shaped region that tapers down at the leade angle until the actual start of the leade. This region adds to the official freebore length as does the length of the transition step. The .45-90 Browning chambers I measured have an effective freebore length averaging 0.267", which includes the transition step length, actual freebore length and the length of the cone shaped region in front of the freebore.

Another comment concerns the official Browning chamber length, which is 2.415 and includes 0.070" of headspace. The actual chambers I measured had a case overall length averaging 2.427", which includes a headspace of 0.070" and a chamber length (inside case rim) of 2.357"

Regards,
Wayne

[Tom Myers]

Wayne,

Thanks for the dimensional values. I have updated my database to more closely reflect your researched dimensions an have redrawn the image above to display the updated values.




Tom,

I retract what I said earlier. I must have been looking at the wrong illustration. Your drawing of the 45-90 Browning/Winchester chamber is right on for the most part. One comment I'd now make concerning your Browning/Winchester specs is the factory official freebore length is 0.150", but the effective freebore length is longer, although not as long as shown in your illustration. As you drawing illustrates, the freebore diameter is larger than the bore diameter. Therefore there's an additional cone shaped region that tapers down at the leade angle until the actual start of the leade. This region adds to the official freebore length as does the length of the transition step. The .45-90 Browning chambers I measured have an effective freebore length averaging 0.267", which includes the transition step length, actual freebore length and the length of the cone shaped region in front of the freebore.

Another comment concerns the official Browning chamber length, which is 2.415 and includes 0.070" of headspace. The actual chambers I measured had a case overall length averaging 2.427", which includes a headspace of 0.070" and a chamber length (inside case rim) of 2.357"

Regards,
Wayne

[Tom-ADC]

Great drawings, not to hijack but do you have one in 45-70 you could share?

[Tom Myers]

Great drawings, not to hijack but do you have one in 45-70 you could share?

I have measured several different 45-70 chambers and a drawing of any one of them would not be significant as the throat configuration differs considerably on each one and none of them conform to the SAAMI specs.

A 45-70 chamber could be similar to the 45-90 the only real difference is the distance from the base to the throat area.

The real advantage having a drawing is that, IF you have accurate chamber dimensions or a chamber cast and know the exact dimensions of a particular bullet, then you can determine whether or not that cartridge/bullet combination that will precisely fit the chamber/throat area of that particular barrel.

[Andy_P]

http://castboolits.gunloads.com/picture.php?albumid=88&pictureid=2237


I have the PTG Shiloh Sharps 45-90 reamer and these specs are accurate for it (according to my measurements). With Starline Brass and a 0.458" boolit, I have about 0.0025" neck clearance. That's tight, and would only accomodate at most a 0.459" slug without using thinner brass or some neck treatment. You need to watch for bulges from crimps and to not flare the mouth too much.