Truing Up the Threads On a Rem 700 Action

B

BumbleBug

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I was looking into "blueprinting" a Rem 700 action & I was surprised to find a number of specialty gunsmithing tools just for that purpose.

One tool is a set of bushings that supposedly centered into the action & a reamer aligned in the bushings bores the hole straight by taking metal off the thread tops. Then the equivalent of a giant tap, using the bushings again, is turned in to re-cut the action threads. Would this really work? Seem like it would just chase the original threads and/or make it sloppy? Have any smithy's used these tools?

It's a 1.5 min video here:

http://www.youtube.com/watch?v=0fU_bGHAfV4

Looks too good to be true! Could this be as good as the ol' hand/lathe work? Any thoughts on this & the whole process.

TIA...

..bug :confused:
 
I think it's a waste of time and money. But there's a lot of marketing hype that convinces a lot of folks to have it done.

All it needs is the receiver face and bolt face squared up to the tenon thread axis then the lugs lapped to full contact. Doesn't matter if the bolt axis is a bit off the tenon thread axis.

There are custom actions out there that are as perfect in every way machinists can make them. None of them hold a barrel that shoots bullets any more accurate than a standard factory action modified as mentioned in the preceding paragraph that's a bit short of precicely perfect in every way.
 
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I'll go a step further and say that IMHO unless one is really going to go all out for the accuracy game, the whole thing is a waste of time and money. Most Remington 700s shoot very well from the factory and if they don't, it might be better to just trade the bummer in rather than spending bucks trying to get it to shoot.

Jim
 
Most threads are designed to mate with 75% thread, but some guns I have seen are around 80%+, and are tight when threaded up. If you remove material, the holding power of the thread drops dramatically.

If you are fitting a new barrel, you always work off the bore. First, you center the barrel in the lathe, off the bore, turn the thread boss on the end, and then thread it. Then when you bore and thread the frame for center, the bores center line should match the bolts center line. You measure the threads on the barrel with thread wires, and calculate the cut depth with them.

This does not take long on a lathe, as after you finish the barrel to spec, you bore the receiver, and cut the threads until the barrel will screw into it, with the desired tightness you want. In other words, you use the barrels threads as a gauge for the receiver. Last, to get the sight on top, you face off the barrel shoulder, until the barrel threads on to the correct position. You can generally calculate how much to face off by knowing the threads per inch, and using where the barrel sits when tight, say a quarter turn until it's there, you remove enough off the shoulder face for almost a quarter turn. Last, you need to remember that you might have to face off the rear too, because of headspacing. The bolt has to close against the barrel, and the chamber length needs to be correct too.
 
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There's rifles shooting as good as or better than current benchrest ones whose receiver's only trued up such that their face and the bolt face is square with the barrel tenon axis in them. There can be a small angle between the bolt way and bolt axis to the chamber axis; doesn't matter. It's repeatable and stays the same for every shot fired.
 
I'm with Bart on this one.

The best thing you can do is square the face of the receiver with the internal threads.

It's rather easy. Brownell sells action facing mandrels pretty reasonable.

http://www.brownells.com/gunsmith-t...ng-tools/receiver-facing-mandrel-prod415.aspx

They are easy to use. Get one for the thread pattern of your action. Screw on the action, and stick it in the lathe between centers. Use a dial indicator to make sure everything is lined up.

Take some lay out ink and coat the front of the action and shave it just to the point you remove the layout ink.
 
I agree to a point, that it can be a waste of money. I have a complete custom 700 in 300 win mag (trued and blueprinted) Krieger barrel, Manners chassis, Timney trigger and custom designed muzzle brake. If I do my part with mk248 mod1 ammo or my reloads it shoots 1/4 to 3/8" diviation at 100 yards. That being said I have a stock 700 SPS AAC-SD with light trigger work that shoots 5/8" at 100 yards with my 178 AMAX load. So is it worth it? It is like a drag racer paying $10,000's of dollars to get an extra 1/10th of a second. Keep what you got and shoot it until it wears out. My AAC-SD, I have less than $1500 counting the scope. The 300WM has many, thousands of dollars in it's creation, not counting all the time...
 
It can't hurt. But how much does it help.

If you are going to true the action and just go in and true the threads. So be it. Just make the barrel threads to match.

If you are doing it for yourself......do it and enjoy.
 
'Course I'd never have a round receiver fitted with a magnum cartridge anyway. Being very familiar with the problems top competitors had with them twisting askew in epoxy bedding from barrel torque when fired when such 'smithing was popular. Every 200 to 300 rounds, accuracy would drop from half MOA at 600 to over one MOA. Rebed and best accuracy returned; for another couple hundred rounds anyway.
 
Thanks for all the good replies & info!

Please correct me if I'm wrong, but before custom actions came along, Rem 700's & 40X's were top choices for target shooters/rifle builders because they were easier to "blue-print". I guess because they are round & have a separate recoil lug. It just seems like if you were going to pay for a premium barrel you'd pony-up some dollars to true up the action too. The point is well taken that you can easily go past the point of diminishing returns on precision & dollars trying for more accuracy.

Out of curiosity, what would be a fair charge for a gunsmith to "blue-print" an action (i.e. true bolt face, true action face, center align threads & lap the lugs)?

Bart B. said:
'Course I'd never have a round receiver fitted with a magnum cartridge anyway. Being very familiar with the problems top competitors had with them twisting askew in epoxy bedding from barrel torque when fired when such 'smithing was popular. Every 200 to 300 rounds, accuracy would drop from half MOA at 600 to over one MOA. Rebed and best accuracy returned; for another couple hundred rounds anyway.
Click to expand...

Man, that's the first I've heard of that one! Makes sense though. :o I did notice that there weren't any "specialty-tools" for truing up Win Mod 70 actions.

Thanks again for all the good replies & advice...

...bug
 
Bumblebug, Win. 70's have won more shoulder fired rifle matches and set more records than any Remington has. There's a long list of items on their "Why Winnies are Better" list backing up why they were the favorite for decades. There's been old Winnies rebuilt some time ago with good barrels and ammo that regularly shot smaller test groups than current medium range benchrest records. The only truing up they need is squaring the receiver and bolt face with the barrel tenon threads and lapping the locking lugs to full contact. Doesn't matter if the boltway is a bit cockeyed to barrel's bore axis; it stays the same for each shot and therefore is very repeatable. And with their intregal recoil lug, a Winnie receiver can be rebarreled several times and the epoxy bedding in the stock will still fit perfectly for every instance.

To begin with for box magaxine repeaters, Winnies are near 3 times stiffer than a Remmie. Go measure them to find out for yourself.

But Winnies were never sold as barreled actions nor actions alone nor at such low prices like the Remmies were. But when more powerful cartridges than the .222 Rem. and .22 PPC were used in benchrest, those round Remmie receivers had to be glued into a flat bottom/sided sleeve to keep shooting one-holers. Winnies come with flat sides and a flat bottom where it counts.

But that's all awash these days with Tubb and Eliseo tube guns now being the most accurate bolt action repeaters on the market and they're so easy to build. However, they don't shoot any more accurate than the Winnies did decades ago.
 
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