Home Forums Hunting & Shooting Gunsmithing Throats and magazine boxes.

I’m sure it’s been asked before but I missed it or didn’t find it.
First how hard is it and what is entailed in making a magazine box larger in a M700 or a M77?
Second. How hard is it to lengthen the throat on a rifle to accommodate a longer bullet say a 280 AI or 7mm Rem Mag with a 160 or 175 so it doesn’t extend ant further than bottom of the neck and into the case body?
Pictures help 😀
Thanks.

Wyatt's magazine box lengthens the OAL about .120, has to be milled out on a Rem 700, ? on Rugers.

The talking heads have spoken a lot of not having the shank of the bullet(intersection of the shank/boat tail) not go past the shoulder neck junction on the case, there are several reasons for this. One reason is that brass flow creates a doughnut at the intersection of the shoulder neck, and this doughnut will squeeze the bullet creating pressure spikes. In small and medium cases, jamming the bullet down in the case eliminates a lot of powder room.

In large magnums, it is usually necessary to have a lot of bullet down in the case or you will not have room to chase throat geometry as the barrel gets worn.

You are in effect, making the chamber longer when you "throat" out the chamber, which does drop pressures some or allow for faster velocity.

I do not agree with the talking heads. I have found in a lot of cases where if you seat the bullet at the top of the powder charge it seems to be magic on accuracy...not a hard and fast rule, but much of the time. You do have to monitor doughnuts, and K&M makes a simple tool to cut a doughnut out when they do form...no big deal.

With super long throats, you are in effect throwing away barrel life, as a bullet will only jump so far before it starts in the barrel crooked.

Brinky72, if you follow through with what you are thinking of doing, then no magazine alteration will accommodate your long OAL's. I shoot 7 mags with a 168g Berger hunting VLD and a 180g Hunting vld, both in barrels with std freebore of .119. Match reamer has .198 freebore. 7 Mag has so much room, you don't have to worry about the bullet taking up powder space. In my 7 Mags, I shoot the 162/168 at 3100 with Retumbo, H1000 is 100 fps less.

280 AI is a much different affair, you will need some freebore due to powder space, and a wyatt's mag box would be helpful.

There are longer detachable mag boxes available than the Wyatt's, but I am not familiar with them. Hopefully someone will chime in and help in this regard. I have two reamers, one with .070 freebore for use of 120-150g std bullets, then a match reamer with .199 freebore for use with the 168-180g bullets.

There are no flies on a std 280 Rem 700 with a 24" bbl where I shoot a 162 at 2900 with IMR 7828, a load right out of the nosler manual #4.

Thanks. You have answered my question/concerns. I’m not a match shooter but like heavy for caliber hunting bullets so, running a heavy 175 is of no concern with standard throat geometry of a 7 Rem Mag or even 280 AI. I’ll check into the Wyatt’s boxes. Thanks.

I have three tang safety M77s with lengthened mag boxes. Gunsmith cut and added material to box and milled reciever to fit. To my knowledge you cannot buy premade boxes like Wyatt's for the Rugers.

Fairly simple job for both operations, I have done it a number of times. I would stay away from the Wyats boxes!

There is something called a "throating reamer" out there. All they do is lengthen throats.

Just don't Google "throating reamer" videos while at work.

Look to Pacific Tool and Gauge


unithroater

Why is that Jim?

LMFAO!

I’ll check out PT&G. Thanks.

IMHO they don't work. they are a POS