Opening up a Remington 700 throat...what does it entail?

[guywitha3006]

I have a suspicion my Remington 700 is to tightly chambered to fire cast projectiles, unless I turn a whole lot of neck thickness off. I already have problems with my wrists so neck turning more than a couple pieces of brass has my wrists throbbing. So on to the question... How much effort will it take my gunsmith to open up the throat a few thousandths? Does he have to take the whole barrel off or can it be left in the action. I plan on talking to him for a more specific price but this is a test the waters for feasibility at this point.

Thanks for the wisdom!

[country gent]

It can be done thru the action with a piloted reamer and a bushing in the chamber to keep every thing straight and true. Better is setting the barrel up in the lathe and indicating in dead true then reaming with a straight tail stock.Much more solid set up, much truer set-up and better control of the reamer. A bushing turned up to fit in the action with little clearence and bore to mach the extension or reamer shank ( even better) can be done and will work one thing is to set the rifle in the vise muzzle down at a comfortable hight as this makes turning and controling the reamer easier.

[Nobade]

Before you do that, have your gunsmith make a chamber cast of it. I have examined many thousands of Remington chambers and never seen one with a throat that was too tight, with the exception of calibers that don't really have a throat like .223 and 270 WSM. What I do see, most of the time, is a throat that is crooked and not aligned with the bore. If it is crooked enough it will certainly interfere with closing the bolt on a round loaded with a cast bullet. You are also unlikely to want to turn necks on a factory chamber. Measure first, cut later!

-Nobade

[guywitha3006]

Nobade, thanks for the advice, I am not opposed to having him cast the chamber(in not trying that again myself) except it is not a Remington factory barrel, is an aftermarket AAC barrel in 300 blackout. Someone mentioned in another thread AAC had some right chambered runs. I turned one case neck down and it the rifle fairly easily chambered the rounds (with a .311" sized boolit). I am thinking I would give the Smith a few dummy cartridges with boolits I want to shoot.

Thanks for the great info, keep it coming, it is greatly appreciated.

[Omega]

What brass are you using? Some brass is notoriously thick for 300 BLK conversion, LC is best. There is a list on the 300 BLK web site of others that will work too.

[guywitha3006]

Omega, I am using Lake City brass (I would say 95% dated to this decade) and still having issues. What are you sizing your boolits too? I want to shoot everything from 90 grain .32 pistol bullets up to the NOE 247s.

[yovinny]

Maybe I'm missing something here ?

AFAIK, 'throating' is relieving/beveling the lands further past the case mouth, so as to fit longer or larger diameter bullets without them binding into the rifling.
How would that have any effect on the diameter of the neck area of the chamber or serve to eliminate case neck turning ?

If you have a 'tight neck' chamber, it may be possible to open it up with a standard reamer without setting the barrel back, but that would really have to be evaluated with a chamber cast.

What diameter are you shooting and how tight are they if you try inserting one into a fired and not resized case ?

Cheers, YV

[guywitha3006]

Maybe throating is the wrong word, I am looking to get the neck opened up. I am sizing to .310 and that plus brass thickness will not even allow it to chamber.

I do not have a fired case to go off of, I shot a few jacketed rounds but didn't think anything of so I threw them in my 300 blackout brass bucket (I have the 700 and an AR chambered for it so up until this point I planned on loading ammo suitable for both rifles). I have not had a chance to shoot any more since. I currently have the rifle taken apart for stock work, so it may be a while before I get a chance to shoot it. I figured I would dig into the "not chambering cast" problem while it was not getting shot.


Maybe I'm missing something here ?

AFAIK, 'throating' is relieving/beveling the lands further past the case mouth, so as to fit longer or larger diameter bullets without them binding into the rifling.
How would that have any effect on the diameter of the neck area of the chamber or serve to eliminate case neck turning ?

If you have a 'tight neck' chamber, it may be possible to open it up with a standard reamer without setting the barrel back, but that would really have to be evaluated with a chamber cast.

What diameter are you shooting and how tight are they if you try inserting one into a fired and not resized case ?

Cheers, YV

[yovinny]

Well, OK..Let me start at the beginning brother.

Your having trouble getting your cast rounds to chamber.
That could be one of several things, but is usually one of two.

Those two being, it might have a tight or short neck chamber, or you might have too short a throat.

Those chamber issues will cause you'r BRASS to jamb in the neck area.
An un-resized fired piece of brass will give you a quick and dirty heads up if it's one of these things.

A short throating issue would cause the BULLETS themselves to stick into the throat area.
A soft cast boolet would probably show signs of this, but might need assistance from some black sharpie coloring first to make it easy to see.

There are other issues it could be, in both categories actually, but I'm betting on the simple throating issue....Both my blackout AR's needing throating to shoot .311 boolets.

First big step is actually identifying which issue your having.

Hope that was clearer than mud ;)
Cheers, YV

[guywitha3006]

YV, clear as mud... yup. I think the gunsmith I use opens shop about noon today, I think I will give him a call and see about doing a chamber cast and verifying the problem. Hopefully I can get a solution figured out soon... it's almost summer around here and the whole point of this rifle was cheaper alternative to plinking with over .22s (I think I can do a 90 grain boolit with bullseye for about $0.06 a round...should be pretty quiet with a can too!). Some one tell me again about all the money I will "save" reloading and casting... I thinking buying Harley's may have been a cheaper hobby in the long run. :bigsmyl2: Oh well, I'm sure I'll save money at some point ... LOL


Well, OK..Let me start at the beginning brother.

Your having trouble getting your cast rounds to chamber.
That could be one of several things, but is usually one of two.

Those two being, it might have a tight or short neck chamber, or you might have too short a throat.

Those chamber issues will cause you'r BRASS to jamb in the neck area.
An un-resized fired piece of brass will give you a quick and dirty heads up if it's one of these things.

A short throating issue would cause the BULLETS themselves to stick into the throat area.
A soft cast boolet would probably show signs of this, but might need assistance from some black sharpie coloring first to make it easy to see.

There are other issues it could be, in both categories actually, but I'm betting on the simple throating issue....Both my blackout AR's needing throating to shoot .311 boolets.

First big step is actually identifying which issue your having.

Hope that was clearer than mud ;)
Cheers, YV

[yovinny]

I know that 'saving $$' pain well,,,lol...But it does work out in the long run.
I only reload in bulk for a hand full of calibers, but IIRC, I have equipment for and reload something like 32 calibers altogether.
Add in casting stuff, bench rest loading stuff and all the other 'accoutrements' (I love that word ;) ) and it produces a pile of $$ that rivals the tools and equipment I use to make a living.

Anyway, best wishes with the rifle, I'm sure the GS will get it squared away.

Cheers, YV

[BK7saum]

I have a custom 300 whisper on a 700 bolt action. Using LC brass, I have to size boolits to .309 or .3095 in order for them to chamber easily.

[guywitha3006]

BK7 do you have any accuracy/leading issues with sizing them at .309/.3095? I plan on mainly shooting powder coated boolits so that gives me a bit of wiggle room for leading, I figure.


I have a custom 300 whisper on a 700 bolt action. Using LC brass, I have to size boolits to .309 or .3095 in order for them to chamber easily.

[BK7saum]

No, my bullet size to 309 or a little over are plenty accurate and no leading issues at all. I actually lube these with 45 45 10 because I occasionally run them through a suppressor

[BK7saum]

I shoot Lake City and Remington brass and do not neck turn either brand of cases

[243winxb]

First measure the loaded rounds neck diameter, it should not be larger than .334" per SAAMI. http://www.saami.org/PubResources/CC_Drawings/Rifle/300%20AAC%20Blackout.pdf If the neck diameter is to big, inside neck reaming may be needed to the brass or reduce bullet diameter.