Shiloh Rifle Forums

DT,
I can see the end of my chambers that have a 7 degree leade. The 7 degree does not extend to the outside of the case, but more like to the ID of the case.

Keep on hav'n fun!
MikeT

Jim,

I believe I now understand your earlier comments. But consider the following. Even with a perfect case length where the lip touches the start of the transition step, the bullet will have to transverse the length of the transition step. In my Sharps .40 with a tight chamber and 45 degree transition step, the step is 0.013” long. Therefore, when the bullet get hits from behind a small portion wrapped with paper will expand into that gap. Wouldn’t it be better if the angle was reduced to 7 degrees? Yes, reducing the angle significantly increases the length of the step but makes for a much easier (read gentler) entry into the bore.

The same problem applies to greasers to some extent &, in some situations, results in a lead ring in front of the transition step. I’ve seriously considered having a barrel set back a bit and rechambered to a neck diameter 0.023” to 0.024" larger than the bullet/groove diameter with an abrupt 90 degree transition step (no taper into the throat). Then, assuming the case lip touches the step, there’s no gap for the bullet to enlarge into. The bullet is driven out of the case neck, does not encounter a step & enters the throat & bore with very minimal if any change in diameter.

But very few if any shooters could maintain a perfect fit of the case length to the transition step. And as you know, all the brass suppliers produce brass with a safety margin to fit chambers of various tolerances and to help minimize high pressures, therefore the brass is typically 0.010” to 0.015” shorter than SAAMI or even custom chambers. Hence all chambers are cut with an angular transition step to help ease the bullet into the throat.

Wayne

The 45 degree angle we talk about in chamber mouths is actually a 45 degree angle on each side or acute angle and when forcing cones are cut I think they are talking included angle or both sides combined. I'm wanting to know which is actually being cut in the 7 degree leade/ throat angle discussed in this thread.

MikeT wrote: ↑Wed Apr 14, 2021 9:32 pm DT,
I can see the end of my chambers that have a 7 degree leade. The 7 degree does not extend to the outside of the case, but more like to the ID of the case.
Keep on hav'n fun!
MikeT

Mike,

That's interesting. Are you suggesting your chamber looks like the following quick illustration I worked up?

Wayne

mike,
in my case it is 7 degrees per side, from o.d of case (or more correctly i.d. of chamber) to bore diameter.
bruce.

incidentally i saw a chamber cast from a 40/2.5 remington hepburn original which was as near as i could estimate about 4 degrees, when compared to my 7 degree reamer. again per side.
bruce.

If you take a look at a standard chamber reamer the end of the neck will have a 45 degree angle into the lead angle from the OD. I see your talking 7 degrees per side.

yes basically replaced the 45 with 7 using a custom reamer.
bruce.

Military rifles of the day (well, my Martini's at least) have no 'case stop' at all, and a very gentle transition to the rifling. So at the case mouth, you have case wall thickness to deal with, but that's it.

OK I understand the angles discussed here, and reviews of chamber cast throat angles etc. But realistically how does the average "Joe" think he has 4 deg or 7 deg or what ever degree, with out an industrial optical comparator or cutting tool pre- setter screen? These small angles cannot accurately be measured with a protractor. A trig. calc. function is kind of un- realistic too?
kw

Deep seated PP bullet in a chamber with the 45º transition.


Deep seated bullet in a 5º transition.
(Look close in the center)

I understand that many of the old rifles were chambered with this funnel shaped chamber end, I have an original roller with this type of chamber. When I look into the chamber, or at the chamber cast I did, there is a noticeably long angled section before any rifling starts. I do not know what the angle is.
Just because that is the way the old rifles were chambered does not necessarily mean it is the best way to chamber a rifle today.

When I decided to go with the Shiloh standard chamber in my .44-77 I did so after a discussion much like this one here. I looked at actual match results. I'm a target shooter and match result are important, and considered my own history with paper patch bullets in standard chambers from Shiloh and others, and I decided what was best for me. I haven't had the rifle a year yet, but the results I have had make me very happy with my choice.

There are plenty of voices on this forum saying that the 7 degree is the way to go, I just felt the other side needed to be heard as well. The OP can decide what is best for him and put his money and hopes on whatever he chooses, he should hear from both sides and make the best decision for himself.

If you are trying to change my mind you have got to come up with something better than the paper ring argument because that one is like saying, since I took the tires off my car I don't get flat tires anymore and I don't buy it.

MikeT wrote: ↑Wed Apr 14, 2021 9:32 pm DT,
I can see the end of my chambers that have a 7 degree leade. The 7 degree does not extend to the outside of the case, but more like to the ID of the case.

Keep on hav'n fun!
MikeT

Mike,
That may well be, but in all the chamber casts, all the chamber drawings and all the reamer drawings I've looked at the 7 degree comes from the outside of the case.

Shallow leads, at what ever degrees go from the chamber wall to the top of the lands, as I have seen in original Sharps and Remingtons. If you still have a step at the end of your chamber after having a lead cut, ether the cutter diameter was too small for your chamber or it didn’t go in far enough.

We all should use what we have confidence in be it a 45º or what ever, this is what I do anyway. I have rifle chambers with several different transitions and I like them all, well maybe almost all baring one.
This is my final approval drawing from PT&G for my long range match .45-2.4 rifle. The 5º taper is .1772" long and it works fine.
I used this rifle now for several years and it put dust collectors on my wall and standing in my cabinet and a glass jar starting to fill up with pins. It put me in the top 10 at the Q and just knocked me under by a tie breaker and held me in third place at the MT 1000 plus it put me in the AAA scope class after the first season I started shooting those matches and the only thing that is holding me down climbing that ladder is those pesky chickens just don't stand still.
I would like to see a good shooter shoot this rifle to really see what it's capability is with a good load.
If something would ever go wrong with this barrel the new one would get this chamber again.
Notice how tight that neck is at .475" compared to the standard .482" used.
No I cant shoot a .458" greaser in this rifle.
Well I have to get to the range and get this new lot of Swiss checked out and get the new DZ scope with a 200 yd zero getting ready for Lodi in a couple weeks.