reamer diagram

K

kman

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anyone here know what to look at on reamer spec to know where to set bullet at lands and groove just to touch,ive got a diagram but its confusing
to me in this area

thanks for any help
 
Bullet seating gauge

Sinclair and i think midway carry a stoney point tool for
establishing the bullet seating depth. It uses a modified
case also available from them. If you have a custom case -
you can make your own with the proper tap and drill from a
fired case.

Since the seating depth will change with barrel use - you will
want to check this periodically.

If this doesn't help you - you could call dave kiff at pacific
tool and gauge - he is a great guy and could tell you what you
need to know approximatley - if your reamer drawing has the
dimensions on it.

Hope this will help you.
 
There is a section just ahead of where the neck ends that is called "freebore". It is usually about .001 or so larger than the bullet but it may not even exist if the reamer was made for light bullets for that caliber. Or it could be real long, like 1/4" (.250). The long example might be for 240 gr. 308 cal bullets and zero length might be for 118 gr. 308 bullets.
Ahead of that section is the "leade" which is often 1º30' per side but may be more or less. Somewhere on this angle is where the bullet will contact. The radius on the bullet, between the body diameter and the point is called the "ogive". That will vary between bullet manufacturers and bullet styles.
All of these variations make it just about impossible to determine COAL with a very high degree of accuracy, it is best to approach it by the accepted method of trying long seated bullets in the rifle and looking for contact on the bullet "ogive".
I see it as being similar trying to calculate how far to push the accelerator pedal to get a vehicle to go exactly a predetermined speed. There are much easier approaches to the issue.
 
Here we go again.:rolleyes:

Jay, if that poor guy is going to be looking at a reamer or chamber print while reading your post he is going to get totally confused and lost, or both. What you call "freebore" is labeled as the "lead" and what you call "leade" is the "throat". Most of us experienced guys know what others are talking about when a chamber is described, even if we use a different language, but a new guy doesn't realize that some of us use different terms for the same feature. So, to be fair, it's important to use the terms that the grinders use even if we don't agree with them.

Edit - To be fair to Jay, Clymer does label the lead as "freebore". But, how many guys reading this forum use Clymer reamers? Not many, I'd say.

JMHO

Ray
 
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kman said:
anyone here know what to look at on reamer spec to know where to set bullet at lands and groove just to touch,ive got a diagram but its confusing
to me in this area

thanks for any help
Click to expand...
You just gotta' try the fit on the actual chamber and actual seated bullet. If you had an accurate scan of the bullet and its ogive and put it in a CAD (Computer Aided Design) system then you could do a calculated guesstimate of the location fit. In reality though, there would still be potential error since the reamer could cut the freebore and leade oversize. A calculation of a 0.0005" oversize leade cone would make several thousands of linear error.

Still confused? Go back and reread my first sentence.
 
good answers so far

HI k-man....the posters have all answered your ?? properly.....I think!!...Im not shure just where ur going..but ...one method not mentioned yet is to ask someon who has a chamber cut with the reamer in question or a reamer similar....and ask them where the particular bullet that you are interested in seats in realtion to case dims....and if their reamer is a Kiff and has a .040" FB and the one you want has a .080 FB ..then just do the simple math and you will be in the "ballpark" ...as stated earlier different reamer mfg. use different terminology.....I hope that doenst cloudy the water tooo much...Roger
 
I'd have to say I agree 100% with Jay's interpretation, and his terms.

Freebore is the 308 or 309 straight part.

Leade (or lead if you prefer) is the angled part that tapers from that 308/9, down to 300.

And, as he says, going from that print and trying to figure where the bullet will touch is about impossible. On a degree and a half, if the reamer cuts just ever so slightly big, or small, that length dimension changes pretty drastically. Measuring when you're done is the only way to know for sure where you're at. You can get in the ball park with the print, but, it's not going to be exact.

Also, as you change bullets, that will affect it as well.
 
I think you guys are missing my point. If he has a reamer print in his hand, and you are trying to point him toward freebore and leade, it's no wonder he will be confused because he won't find those term on it. He will see the term throat (which is what he is really after) but you don't talk about that. We have to use the same terms that the grinders use.

When's the last time you had Dave Kiff make you a leade reamer????

It's the THROAT!!!:eek:

Ray
 
from SAAMI GLOSSARY

FREE BORE
A cylindrical length of bore in a firearm just forward of the chamber in which rifling is not present. Associated with bullet jump.

THROAT
See Leade (Lead).

LEADE (LEAD)
That section of the bore of a rifled gun barrel located immediately ahead of the chamber in which the rifling is conically removed to provide clearance for the seated bullet. Also called Throat or Ball Seat.


JUST TO KEEP THINGS ON AN EVEN KEEL....LOL

ohh and atleast one major reamer manufacturer has the terms backwards....so be careful

mike in co
 
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