I have a rifle that has no lead I would like to open up. Is there a shade tree gunsmithing way to do this? Thanks, Jim the Plumber

Jim-You can get a throat reamer from Brownells or
other places.A lot of smiths have them too.
Can't use roto-rooter from your tools as it isn't small enough..Couldn't Resist..We got to have fun..Ed.

Buy a throating reamer and handle from a reamer maker. With care, one can do a good job. Biggest problem is knowing how far to go, and when to stop, it is real easy to make the throat too long. I have some special gauges I made up for throating, and a throating reamer holder that has a positive stop that is easily adjusted for depth.

But, you gotta remember, the new throat will not be absolutely concentric, straight and true with the original chamber. Only way to have a really true throat (sounds sort of spicy, huh?) is to have the reamer ground correctly and cut a new chamber.

However, for a general purpose hunting rifle, really will not matter much if you cut a new throat with a throating reamer. Where the nit picking comes to real play is in long range precision rifles, benchrest, etc.

My guess is your chamber does have a throat, or lead, or freebore, whatever one calls it, but it is just not enough for the bullets you are using.

[ 03-16-2003, 20:07: Message edited by: John Ricks ]

Now Ed, any good gun plumber like us knows that special deep throat 'rooters exist for the big bores, just a well kept secret. They work like armorers' pull through headspace reamers, the snake extends out the muzzle, just keep turning until the bolt closes.

Speaking of big bores, what is the case length of your 458?

[ 03-16-2003, 20:12: Message edited by: John Ricks ]

JTP,

Think of the throat as the "birth canal". What happens to the bullet here, will affect it the rest of it's life... Which should be short and to the point!


Malm

[ 03-17-2003, 01:30: Message edited by: G.Malmborg ]

Cutting a new throat is sometimes a good thing. There is a lot of support for the theory that a parallel throat is much more tolerant of seating depth variation, and that a lot of rifles are picky about seating depth due to the older style of throat which is tapered. Whichever one is SAAMI's for the cartridge is the one the reamer manufacturer uses unless you buy a custom reamer. For this reason, some cartridges are generally temperamental and some aren't. If you use a throating reamer, you will have a parallel throat.

Follow John Ricks Advice! He's dead on!-Rob

Throats are tapered, gotta have an easy entry into the rifling. Some have different angles. Common accuracy angle is 1-1/2 degrees per side. Many factory throats are as much as 3 degrees, some more. I have used 1 degree throats for 1000 yarders, jury is still out on this one.

There can be confusion on the "freebore" section, this is the area ahead of the neck of the chamber, but before the tapered throat. Most gents lump the freebore and the tapered area together and call it the "throat". Most freebore sections have parallel sides.

Now, have a different story in the neck area of the chamber. This is where the neck of the case fits. Most factory and SAAMI and CIP chambers have tapered necks. But nearly all match, or benchrest, or long range precision rifles, what ever you call 'em, have parallel necks. Here we are fitting the case neck to the chamber, and we want minimum movement of the case in the chamber, this helps to align the bullet in the center of the bore. And here also is where we get into the world of turned necks on the brass, seating bullets into the lands, tight chambers, and all those things that can run pressures sky high if you do not know absolutely what you are doing.

A tapered neck is ideal in a big bore Dangerous Game Rifle chamber, we need all the help we can get to be sure the cartidge goes in the chamber fast and easy and the bolt closes!!! We ain't worried about 1/4" goups at 100 yards, all we need here is to be able to hit a baseball at 25 yards or less with a 500 grain bullet.

If one wants to learn more about throating, buy the "Gunsmiths Book of Chamber Prints" from Dave Kiff at Pacific Tool. Has hundreds of drawings, including SAAMI, CIP,Wildcats, custom reamers, etc, and shows all the chamber dimensions and throat angles.

[ 03-17-2003, 09:36: Message edited by: John Ricks ]

And though it isn't "quick & dirty" or "shadetree", you can do a pretty good job of extending a throat with a throating reamer without getting the throat harmfully non-concentric with the rest of the chamber.

Use a true floating reamer holder in the lathe tailstock, do a good job of centering the actual bore, and use a reamer pilot which fits the bore within .0002". With due care you can do a remarkably good job of deepening even benchrest throats.

As to throat angles, in cast-bullet benchrest, throat angles of as little as 1-degree included (1/2-degree per side) are not unusual. Helps ease that fragile alloy into the rifling....