Normal Throating of .223/5.56 chamber in a Stevens 200

[The Old Coach]

OK, new to this forum, and this Stevens 200 (.223 Rem) is the first of these newfangled bolt action Savages I've ever owned, (I'll admit to a 99 or two). Also new to the .223 cartridge, having spent a good few years using the old 2R Lovell in various single-shots.

Bought this second-hand, largely because it had the barrel shortened to about 16 1/2 inches, by a "world class gunsmith". The idea being to have a lighter, handier rifle, since I ain't getting any younger, and to switch to a cartridge for which brass is a little more plentiful.

Now, I haven't fired a factory cartridge since Reagan was in office, so I of course set out to find the optimum OAL for the various bullets I planned for this rifle. And I am slightly stunned. Take the ubiquitous 62 grain M855 milsurp bullet f'r'instance. Load that so that it fits the magazine, and I've got a monumental .170" of bullet travel before contact with the lands. Has Savage taken a page from Roy Weatherby's book and free-bored their factory barrels? Or has this so-called "world class gunsmith" done a little "world classing" to the throat in this one?

At least I have the consolation that a barrel change won't be too much trouble. . . . .

[bigedp51]

I have a Stevens 200 in .223 and two AR15 rifles, the throat on my Stevens 200 appears to be slightly longer than the throats on my two AR15 rifles. I tested this by just bumping a case in a neck sizing die so the neck would just hold a bullet but allow it to move with a little force. I chambered this test round in all three rifles and measured the OAL of the test cartridge.

If the Stevens 200 had a standard SAAMI .223 throat the AR15 throats should be twice as long as the Stevens 200 but it was not.

My tests are shade tree mechanic tests and there are specific gauges made for proper testing of the throat. The reason I say this is you have throat diameter, throat angle and throat length on the various type .223/5.56 chamberings. Also Savage has .223 rifles with the following twist rates, 1 in 14, 1 in 10, 1 in 9 and 1 in 7 and I assume the throat lengths vary for the use of heavier and longer bullets.

Read info below.

223 vs 5.56
http://www.savageshooters.com/showthread.php?21639-223-vs-5-56

[The Old Coach]

My tests are shade tree mechanic tests and there are specific gauges made for proper testing of the throat. The reason I say this is you have throat diameter, throat angle and throat length on the various type .223/5.56 chamberings. Also Savage has .223 rifles with the following twist rates, 1 in 14, 1 in 10, 1 in 9 and 1 in 7 and I assume the throat lengths vary for the use of heavier and longer bullets.

Thanks for your input. Your test isn't "shade tree" at all; we've been doing that ever since we had metallic cartridges. All the "special gages" do is quantify measurement so it can be reproduced quickly and with some standardization, without resorting to the Cerrosafe casting technique. (Which I actually prefer. Just haven't gotten the round tuit yet.)

Your compendium of info in that other posting was helpful. I have studied the SAAMI drawings already, but the stress analysis I had never seen before.

BTW my 200 barrel is a 9 inch twist.

Phil

[bigedp51]

Below are the three methods of measuring chamber pressure for the .223 Remington, all three pressure are equal and the same, and they are just measured by different methods.

SAAMI copper crusher 52,000 cup
SAAMI piezo transducer 55,000 psi
European CIP piezo transducer 62,000 psi

Shade tree covers a lot of ground, something is wrong with the chart below and the readings. It looks to me that the strain gauge was reading slightly low and the readings should be SAAMI copper crusher method or in CUP.

http://i122.photobucket.com/albums/o254/bigedp51/barnes-pressure.jpg

My bullet method of checking the throat length was shade tree and ball park, the only true way to check is by a chamber cast or calibrated throat gauges. And the only sure way to know what your chamber pressure is with proper pressure measuring equipment.

[Tripleduce]

Phil
I'am also new to this site.
I just purchased a used model 10 in .223 with a 9 twist. I'am also new to Savage and saw that this gun also must have a lot of freebore.
My 60gr AR mag length (2.260) had over .100 jump.
I'am a BR shooter and as such pay a great deal of attention to distance into or out of the lands. I was doing some load development with the Savage and don't think I could shoot anything much lighter than 60 to 70 grain bullets. Even with those I need to jump .040-.060 to have the bullet a reasonable distance into the case. Maybe 3/4 of the bullet dia.
I'am having trouble finding out just how much freebore in have. I have never tried cerrosafe but I might need to try it.
I may need to try another barrel too.

Ben

[The Old Coach]

@Tripleduce - - Well, that makes two of us, at least. And as I understand it, my 200 is just a cheaper version of your Model 10, too. Maybe Savage DID throat some of 'em long ? Need more data. . . . . In any case it doesn't give me a warm fuzzy feeling.

I do reckon however that in spite of my barrel being very short already I could set it back by .200 or so and rechamber it. Very easy to do since there's no fixed shoulder in this design. If that doesn't work then new barrel, which means $$$$.

[BoilerUP]

I had an 11 Hog Hunter barrel that had, by my estimation, 0.035" of freebore. To the lands was 2.39" with a 75gr HPBT, where in an older 12FV barrel lands were at 2.29".

[scope eye]

I could not help but notice, Mr Coach that you quoted something from 51, and I don't see his post, and if he deleted it, it would be marked as deleted?

Dean