Need some help with throat depth & bullet choice

[dharris]

Ok, new guy with a question - go figure. (honest I've searched and I'm still confused).

Going to try the F/tr world of competition this coming year. Easing in gently (read low $$) so I've started with a Savage Mod. 12 F/tr rifle, 30 inch barrel, 1 / 12 twist - purchased in Nov. this year. I've read about varying chambers in this rifle (95 Palma or Obermeier (sp?). or ??) and can't find a definite answer on what is in this gun. I would like to run the Berger 185 Jug round to help with wind if I can. I've measured the chamber with a Stony Point / Hornady gage and come up with the following data: (measurements with gage were from "seating" bullet into the lands fairly firmly, but just below where the bullet would stick and have to be "pushed" out from the front - so if this is wrong, please educate me).

Oal base to Ogive
2.857 3.2
2.889 3.234
2.886 3.229
2.887 3.23
2.889 3.232
2.8885 3.231
2.8865 3.23
2.885 3.229
2.8835 3.226
2.889 3.231
2.888 3.23
2.888 3.231
2.888 3.2305
2.8885 3.2305
2.8865 3.23
2.8865 3.229
2.886 3.23
2.8865 3.229
2.886 3.23
2.886 3.229


Std Dev 0.006871901 0.0015714
Avg 2.887026316 3.230052632
Median 2.8865 3.23

(forgot to mention that the first measurement was tossed for the calc's as it was a measurement error on my part - gage slipped after removing from chamber and I did not notice until making more measurements)

Now for the question. Using the 2.8865 median or 2.887 average measurements along with the 3.23 for base to Ogive, this puts the boat tail almost into the case (below shoulder). If I now set the bullet back 10 to 15 thou. the boat tail will be definitely encroaching on the case volume. From what I've read, that would hinder volume & ability to reach 2650 fps for this load without going over pressure???

Should I try the 185 and work up to see if I can make a load safely or just try to find a gunsmith here in No. Calif. to lengthen the chamber for me (anyone know of a good gunsmith familiar with Savage in Nor Cal?)? Or, just go to the 155 gr. to learn on?

sorry for the lengthy post / question

thanks for reading

Dave H.

[foxx]

Good question, and I don't know the answer, but I would think it best, economically speaking, to initially go with the shorter bullet and see how well you are able to work it within it's limitations. There's a good chance you aren't good enough of a shooter, yet, to make the most of the longer bullets and the advantages they offer at long range. You can always have the throat lengthened later.

So... I would learn on the shorter bullets. If/when you find you are competitive at shorter range and not at long range, you may very well be "good enough" to benefit from the longer bullets.

[foxx]

Also, I wonder if it is wise (economically speaking) to lengthen the throat of a factory barrel. It might be, I don't know. It might be better to just sell it new, unfired, and apply that money towards a better aftermarket barrel chambered to your specs originally.

[LongRange]

like foxx said i wouldnt throw money at a factory barrel...with that said id use the 2.888 as your starting point(touching lands)as its the most consistent number...seat .025 back from 2.888=2.863 and start your load development there and not worry about case capacity...find a max charge weight you are comfortable with and shoot an OCW test.

[foxx]

And that doesn't mean factory barrels aren't any good. They can be very good, but you don't know until you've shot it a bit, and by then you lose resale value. So... if you decide to lengthen the throat right away, I'd sell it new and get an aftermarket barrel throated the way you want. If you decide to start without a longer throat and determine it IS a good shooter and you DO decide to lengthen the throat, you probably can justify doing so at that point.

[dharris]

thanks for the inputs everyone
Dave H.

[FW Conch]

If you decide to shoot the 185's, I would be interested to hear how they do with your 1/12 barrel twist?

Thank's,,,Jim :-)

[dharris]

Ok everyone - I've finally been able to do some load work-up with the 185's but wound up having more questions than answers / results.

Testing conducted with Laupa Palma brass, BR4 primers, Varget powder & Berger 185 Juggs, seated 0.020 off of the lands.

Since I don't have the Berger load manual (on order, just not hear yet) for Max load I read this forum and AccurateShooter and (still confused) started with 41.1 gr of Varget.

41.1 = 2480's fps
41.5 = 2560's fps
41.8 = 2580 fps +/-
42.1 = ~2598 fps
42.4 = ~2600 fps
42.7 = 2644 fps
43.0 = 2662 fps
43.3 = 2672 fps (only 1 round fired)
43.6 = 2675 fps (only 1 round fired)

I did not load up enough of the 43.3 & 43.6 to do the ocw test with these charges.

Ladder test showed

42.1 - 42.4 showed similar group position on the ladder test (2 shots each powder charge) but too slow to be competitive at 1000 yds.

42.7 & 43.0 have acceptable velocity (per berger ballistics calculator)but are not close enough together to believe they are in a node.

I think that 43.0, 43.3 & 43.6 may be starting a higher node, but not sure how high up I can safely go with powder charge (none of these loads showed any pressure signs during testing in 60 deg. ambient temps.

Could someone look in a Berger reloading manual and tell me what the max recommended load is for Varget & 185's ?

I can't seem to figure out how to insert a photo of the OCW targets for 42.1 thru 43.3 charge loads.

any help appreciated.

Dave H.

[LongRange]

http://i1239.photobucket.com/albums/ff515/LTT-/Mobile%20Uploads/1454761300.jpg (http://s1239.photobucket.com/user/LTT-/media/Mobile%20Uploads/1454761300.jpg.html)

http://i1239.photobucket.com/albums/ff515/LTT-/Mobile%20Uploads/1454761493.jpg (http://s1239.photobucket.com/user/LTT-/media/Mobile%20Uploads/1454761493.jpg.html)

[dharris]

Thanks LongRange - -