Range Report: Savage 99A 375 Win.

[Mainehunter]

Yesterday, I finally got a chance to test some loads in my Savage 99A 375 Winchester.
Here are the loads I compiled from on-line info, books and using the QuickLoads program.

Bullet: Montana Bullet Works, 310 LBT sized to .377, BHN 22 heat treated.
Cases: Starline 38-55, sized and trimmed to 2.075
Primers: CCI 200
Powders: IMR 4198 (old container of DuPont) & IMR 3031
C.O.L.: 2.70 light crimp using Lee FCD.

The objective was to get around 1600 f.p.s. give or take but no more than 1700 f.p.s. and really didn’t want a thumper load. All loads were run through my Chrony to check for velocities and was placed back around 10 feet. Targets were at 50 yards using factory front and Williams rear peep sight. With 4 shot groups, 5 rounds each for a total of 20 rounds, I tried IMR 4198 first. The best on target and Chrony results was my second load consisting of 27 grains of IMR 4198 (one on the left):



LO: 1541
HI: 1571
AV: 1560
ES: 29.7
SD: 12

Not bad and recoil was manageable even though I brought the wrong counter weight for the led sled, next up IMR 3031. Out of the 4 shot groups that were fired my last group fired more consistent through the Chrony but it didn’t group as well on target. This charge was 33 grains of IMR 3031. (one on the right)

LO: 1669
HI: 1679
AV: 1674
ES: 10.3
SD: 4.5

There are a few things I’ve learned from this range session and they are:

1.Even though IMR 3031 was dirtier, it did shoot on target better than IMR 4198.

2.When it comes time to do more load testing on the Savage, I need to scope it for load development. The sights on it now aren’t cutting it and I know it could shoot better.

One of the things I noticed that around the case mouth’s on all of them particularly the cases that were filled with IMR 4198 it’s leaving a thin coat of sticky residue. To me that looks like back pressure, like the case or bullet not sealing properly. Here is the pick:



I wished the 310 LBT bullets could’ve been sized bigger to .378 or .379 but they were only available in .377. Why? I ended up fire lapping the bore since it did have a noticeable restriction near the breach. The bore diameter is .3755 on the lands and .3775 in the grooves. Also, after fire lapping I fired off a few Ranch Dog 235 grain bullets that are sized to .379 to season the bore. With a small charge of IMR 3031 the Ranch Dog bullets actually grouped better the 310 LBT.

So there you have it. Overall I’m somewhat pleased of the results and there’s room for improvement. Any comments or suggestions is greatly appreciated!



Mainehunter

[missionary5155]

Greetings
That rifle - caliber combination is on my list also. Something about caliber .375 I like. Saw JES Reboring had a caliber .375 Whelen ready for sale so snatched that one up 2 month ago.
A question.. Have you checked the throat diameter ? I pretty much only shoot cast bullets. Have found that throat diameter really is the key to getting a lead bullet started out right. I think you will find your throat close to that .379 diameter the RD bullets were. I would not be surprised if it is around the .380+ side.
But I sure would be looking for fatter bullets. I agree with you.. Why the bullet people think all barrels are the same ? Cast bullets need to be tailored to the barrel diameter plus some. Just another reason I make my own.
But you sure have a nice hunting rifle there. Caliber .375 is a no loose way to go.
Mike in Peru

[Mainehunter]

Greetings
That rifle - caliber combination is on my list also. Something about caliber .375 I like. Saw JES Reboring had a caliber .375 Whelen ready for sale so snatched that one up 2 month ago.
A question.. Have you checked the throat diameter ? I pretty much only shoot cast bullets. Have found that throat diameter really is the key to getting a lead bullet started out right. I think you will find your throat close to that .379 diameter the RD bullets were. I would not be surprised if it is around the .380+ side.
But I sure would be looking for fatter bullets. I agree with you.. Why the bullet people think all barrels are the same ? Cast bullets need to be tailored to the barrel diameter plus some. Just another reason I make my own.
But you sure have a nice hunting rifle there. Caliber .375 is a no loose way to go.
Mike in Peru

When I did a chamber cast back in the spring and yeah, it's on the big side like .380 and also the throat is long but I don't recall the length. I think the next time around I would like try some in .379 and I should see some improvement in accuracy.

Mainehunter

[missionary5155]

Howdy
Throat length is not quit so bad as that pesky diameter. I always try to go at least .001 over throat diameter "if" the chamber-brass combination will permit. Sometimes the chamber is not fat enough for the bullet and brass to fit. But if the loaded round chambers with that fat bullet I have never been disappointed.
Well I had to go look at Gunbroker and there are two going through the days. I will watch them both and droowl on the keys daily. Have my son in Minnesota watching as he works at a shop that gets alot a tradeins. May yet snag one this year.
Good shooting. Keep the rsange reports flowing. I will glean the good load info and try those first.

[AJMD429]

So there you have it. Overall I’m somewhat pleased of the results and there’s room for improvement. Any comments or suggestions is greatly appreciated!

I think RanchDog no longer sells bullet molds (http://www.ranchdogoutdoors.com/), but I'm pretty sure there are fellows out there who USE his molds and sell the bullets; several people I've talked to really like that 375 bullet his molds throw. I have some from Carolina Cast Bullets - http://www.carolinacastbullets.com/Ranc ... doors.html.

[Mainehunter]

AJMD429.... I do have the 35 Rem & 30 cal mold from Ranch Dog but I've missed the boat on the 375 but have ordered a few hundred from Carolina Cast this past spring. I've noticed they have raised their prices a tad but still a good deal.

Mainehunter

[3leggedturtle]

Wonder if that load will shoot thru a whitetail Not to mention the 3-4 bison standing behind it Do you plan any penetration test. Haven't loaded my 375 yet, but I hear-tell Its one of the hardest and strongest cases made. Not surprised they didn't seal the 1st firing. I have Starline 45/70 and 45C brass that needed 2 firings to expand to fit their respective chambers.

[handirifle]

Might suggest annealing the case mouths, and crimping the bullets when seated. Might improve accuracy too.

[Mainehunter]

Might suggest annealing the case mouths, and crimping the bullets when seated. Might improve accuracy too.

Bullets were lightly crimped with Lee Factory Crimp die but annealing the case mouths is a good suggestion. Thankx!

Mainehunter

[Rusty]

If you like the LBT bullet just go right to the man. Veral is easy to talk to will make you exactly what you need for your rifle.

[Mainehunter]

If you like the LBT bullet just go right to the man. Veral is easy to talk to will make you exactly what you need for your rifle.

I've been already planning to have a mold cut from him once I figure out what size I need. I have a couple of his molds already, great guy to talk to.

Mainehunter

[Sixgun]

Looking at the groups show that you have a nice balanced load.

The rifling twist in your rifle is for the 200-250 gr bullets so the 310 gr. your using will not shoot as well. They will give ok hunting accuracy to 100 yards or so.

You need to get a larger diameter bullet, at least .378 or .379. The reason you are having trouble finding .379 dia. 300 gr bullets is because the bullet makers know this bullet is for the .375 win. and guys seldom size to .379 for their 375's.

My 375's will shoot those groups at 100 yards but I'm using 270 gr. bullets at .379 and I use blown out 30-30 brass so the larger bullet will fit the chamber.---6

[Mainehunter]

Looking at the groups show that you have a nice balanced load.

The rifling twist in your rifle is for the 200-250 gr bullets so the 310 gr. your using will not shoot as well. They will give ok hunting accuracy to 100 yards or so.

You need to get a larger diameter bullet, at least .378 or .379. The reason you are having trouble finding .379 dia. 300 gr bullets is because the bullet makers know this bullet is for the .375 win. and guys seldom size to .379 for their 375's.

My 375's will shoot those groups at 100 yards but I'm using 270 gr. bullets at .379 and I use blown out 30-30 brass so the larger bullet will fit the chamber.---6

After doing some research and talking to a few shooters who have shot the 375, I thought 300 +/- grain cast would do well with it's twist rate, maybe I'm looking at it wrong. I know the 310 LBT I used are under sized and would like to try some sized to .379. I do have a single cavity Lyman 375449 I could try but it would have to wait until after hunting season.

Mainehunter

[BigSky56]

Try Beartooth bullets they put them out in different dia for the 375 cal guns and are a LBT style and in a couple three weights. danny

http://beartoothbullets.com/bulletselect/index.htm