Savage Chambering Method

[Stonewall]

See the last post on page 1.

http://savageshooters.com/SavageForum/index.php?PHPSESSID=dje8t0i10o8adrcq690tbdvhl4&topic=20658.0

Glenn

 

[Bnhpr]

It's a wonder they shoot as well as they do.

well....some of them.

 

[Crow99]

I would imagine that Savage isn't the only manufacturer that uses this or similar methods. One well known maker of single shot rifles probably does as well. I've set several of their barrels up, actually "successfully" rechambered a few, and the chamber misalignment ranges from "more than I'd like to see" to "astounding..."
"Factory" methods and "custom" methods do differ, as do the prices for each. You tend to get what you pay for....

 

[jackie schmidt]

Manufacturing

Any large scale manufacturer, such as a firearms maker, must rely on the latest state of the art equipment in order to produce a product within production tolerances, and at a competitive price.

The proof of any operation is in the final results. Savage has a reputation of building Rifles with exceptional out of the box accuracy, when compared to their competitors.

It would surprise many Machinist Purist exactly how some things are made in todays world of computer aided design and manufacture.

Remember when Chevrolet introduced the connecting rod manufactured with the "powdered metal tech", we all cringed. How could that thing possibly be as strong as the forged offerrings we enjoyed through the years. Well, it was, and still is.............jackie

 

[alinwa]

good post Jackie

al

 

[Bnhpr]

I've loaded for and sighted a half dozen Savages, and have seen great variance in out of the box accuracy, with that small sample at least.

Looking at the setup, I guess it's no worse than putting a barrel in a collet or CNC lathe and running the tooling in. Your at the mercy of exterior to bore runout.

Now if a manufacturer could get a machine that could shoot into the bore with a laser, where the throat forms. And the machine could align itself to that bore.

Boy, they could really establish an accurate chamber.

Is there any such technology out there?

 

[frwillia]

Now if a manufacturer could get a machine that could shoot into the bore with a laser, where the throat forms. And the machine could align itself to that bore.

Boy, they could really establish an accurate chamber.

Is there any such technology out there?

One could auto-align the bore using automated spiders on each end of a specially made spindle, then use a muzzle flush, chamber it with a coolant fed core drill, roughing and finish reamers, and get a chamber in maybe three minutes every bit as good as the best custom chambers. The technology (instrumentation, servos, etc.) to do that exists, but as far as I know the machine hasn't been built to apply it to chambering rifle barrels.

It would be slower than what Savage is doing if for nother reason than because the barrel would have to be fed thorugh the spindle instead of just placed in a clamp (vise) to hold it.

Savage could use some of the same technology to align the bore of the clamped barrel blank at station 1 in their drill press, then do the chambering in successive stations and get relatively close if the machine correctly aligns to the stations - it wouldn't be as good as spinning the barrel, but it might be an improvement.

The deciding factor would be whether or not the incremental inprovement in accuracy would even show given the no better than poor (package rifles) to fair (model 12 target rifles) quality of the factory barrels. The accuracy factors are an RSS combination so even with one factor (the chamber) perfect, the rest (barrel, bedding, trigger, crown) will still be acting with full effect and the group won't shrink all that much. To get the benefit of better chambering may take better barrels and better bedding/inletting (which they appear to be trying to do with the new aluminum chassis approach) - also costly.

So it's a balancing act across many factors of material, process, and quality trying to get the most accuracy for the buck in a very competative market place. That's part of the reason the article comparing the new sluminum chassis bedding to the normal factory bedding didn't show much improvement.

The bottom line is don't look in the barrel with a borescope if you aren't willing to replace the barrel. In the lower grade of rifle the bore will look pretty ugly - but the accuracy will still be suitable for the rifles intended use (reliably hitting a deer in the kill zone at 100 yards for example).

Fitch

 

[Bnhpr]

I spend a lot of my time these days in numerous high tech machine shops, and have wondered if this tech could be applied to rifle manufacturing. I guess the average joe just doesn't care, or is unaware of accuracy potential.

Like you say, improving the chambering process is really not that important if the bbl is e.

Ya cant make a silk purse from a sows ear.....

 

[John Kielly]

I have some catalogues going back to the sixties. Then, you'd pay a couple of hundred bucks for a hunting rifle you would be comfortable carrying. These days, the market seems reluctant to pay more than $5-800, so why be surprised at the shortcuts the manufacturers take to sell at that price?

I'm more than sure that a car costs more than two or three times the dollars that the sixties stuff did, maybe houses still do.....

 

[BillPa]

See the last post on page 1.

http://savageshooters.com/SavageForum/index.php?PHPSESSID=dje8t0i10o8adrcq690tbdvhl4&topic=20658.0

Glenn

Fred's comments describing the operation.

Savage does not gauge their chambers like a common gunsmith would, it is a very different and precision process. A sleeve cap is screwed on the chamber end of the barrel. This cap has a step ground on he end of it half way across.I don't recall exactly how deep the step is,(it looked about .030") but it serves as a range of measurement. There are 5 gauges, called stand-off gauges, inserted into the chamber, each with their respective purpose. The first gauge is a throat gauge. The end of the gauge must be between the top of the cap and the step in the sleeve cap, essentially a go,no-go in height. The next guage is a headspace gage, same deal, it must be between the steps. The next gauge measures the diameter at the shoulder using a taper that will let it fall, again, between the steps. Same thing with the next gauge, it measures body diameter close to the case head. The last gauge measures the chamfer on the chamber mouth. Lastly, about every 5th barrel has a chamber cast to check for tears,scars and any other irregularity.
The way these gauges work on a taper, for every .001" the chamber differs in diameter, the gauge height would change about .030".
As far as wear on the reamers....the finish reamer cuts very little material. The 1st tool is a chamfer cutter, the next is a core drill, then a rougher reamer, then a finish reamer, and finally 20 strokes with a flexi-hone. Contrary to common belief, the barrels are NOT chambered in a lathe. Instead they are held stationary in the vertical position and are machined by a cnc turret drill press, while oil is pumped from the muzzle end.