- March 29, 2016 at 1:09 pm #26549
Doc 44 and I recently picked up some Husqvarna M46s in 9.3x57mm. There is not a whole lot of reloading data out there for the cartridge, so I’ve been turning to Quickload for assitance. Normally Quickload’s predicted velocity is pretty close to what the Chrony actually reads. This has not been the case with this one.
I’m pretty sure that the culprit is the .565″ of freebore in front of the chamber. I ran into a similar situation when helping a buddy work up loads for his 340Wby, but with this one we had pleanty of tested reloading data to compare to.
Another factor is the chamber cast showed the chamber to be roughly .010″ larger than the cases.
The only powder I’ve tried so far is CFE223 with 270gn Speer seated to the bottom of the neck at 3.050″ with Win LR primers in PPU cases. All of the primers are rounded indicating low pressure. I tried some Norma brass also and had backed out primers, again indicating low enough pressure that the case didn’t expand to fill the chamber fully.
I’m also getting sooty necks after firing, which again should indicate very low pressure.
Charge Quickload Actual
51gn 2305 2022
53gn 2394 2108
55gn 2482 2206
56gn 2527 2242
The rifle is built on a Swedish M96 action. The 6.5×55 has a max pressure of 55kpsi, so with a similar case head dimension I’m shooting for 55k or less for the 9.3×57.
The powders I have on hand are IMR 4064, 4320, 3031, RL-17, CFE223, LeverRevolution, and Win 748. I also have some 4759 and 4227, but they are probably way too fast for this round.
About the maximum COAL that will fit and feed from the magazine is 3.175″.
Any thoughts on how to wring some reasonable performance from this round, while still being safe?
One thought I had is to add the freebore to the COAL in Quickload for 3.615″ for an estimation of pressure and velocity and it gets me alot closer to what the chronograph is actually reading.
- March 29, 2016 at 6:47 pm #26565bjornbModerator
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I’m not sure you’ll get great performance from this cartridge using a heavy bullet like the 270. This caliber/cartridge is virtually identical to the 35 XCB, and my experience with the 35 XCB is that the sweet spot sits right around 225 grains. Using this bullet weight will allow you to use stout charges of both 3031 and 4320, which are the 2 powders I would recommend for a 35-cal (or 36-cal) bore. You’ll easily reach 2500 fps with a bullet in the 200-225 range using these powders.
Any slower powders will give diminished returns.
I did a QuickLoad simulation using a 24″ barrel, and that heavy 270 will cause overpressure before you can get any decent speed. You’ll be stuck around 2200 fps.
- March 29, 2016 at 7:27 pm #26566
Did you do anything different in Quickload to compensate for the .565″ of freebore?
What I’m running into is the actual velocities are much slower than what quickload is predicting.
I got out today and shot some with RL-17, with the 270 Speer loaded to 3.05″
Charge, Quickload, Actual
53gn , 2303 , 2087
55gn , 2399 , 2229
56gn , 2447 , 2270
57gn , 2494 , 2298
The 56 and 57gn loads finally had clean necks without any soot on them.
All of the primers had rounded edges on them.
The 56gn load started to have the body expand near the base, but the shoulder was still rounded, so I think the pressures are still low and in the safe zone.
I think that I could live with the 57gn load.
I read on another forum about using 4895 with good results, so I may stop and see if I can get a pound of it today.
I’m not finding anything lighter than 250gn bullets anywhere. The 232gn Norma bullet might be nice to try if I can find any.
I’d like to get a bullet mold for it, but I’m wondering how it will shoot with the huge freebore.
- March 29, 2016 at 10:45 pm #26575HarterParticipant
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A gentleman ran some quick load numbers for me for the 6.8 Rem. The data mostly agreed with what was delivered, there was 1 powder that departed wildly. 4350 showed a 105% load volume charge that was actually just 75% or using that guide space allowed for a 126% charge .
Not to throw stones but when data doesn’t match results then there’s a good chance that the results or data is flawed. You could check it against 8 and 9×57 data as a base line for the slowest powders .
- March 30, 2016 at 1:48 am #26588seaboltmParticipant
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I would think the 9×57 would be close to the 358 Winchester. Any starting load for the 358 I would think would be on the low end of pressure for the 9.3×57. Large freebore adds to more pressure drop. On my 6.5 Ackley’s and custom 257 Roberts I usually pick the bullet I want to use and then use a throat reamer to give the proper freebore to chamber the desired round, particularly since mine are on intermediate options. This comes in to play since the Husky is an intermediate length action. Most US data for x55 and x57 or 257 Bob or 6mm Rem data assumes a short action. With an intermediate action you have more options.
- March 30, 2016 at 11:50 pm #26646ken campbell iowaParticipant
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looks as tho your magazine is limiting your oal a bit short of rifling contact . you might want to consider loading the first round out for accuracy and loading it by hand …. that is if that load is significenlty more accurate to warrant the hassle.
i had a similar problem with my 257 weatherby, with long freebore ; 1.3 moa when magazine length….1.0 when long seated . important when coyote hunting . oh, seldom needed 2nd shot on coyotes ( g ) …
- March 31, 2016 at 7:46 am #26657bjornbModerator
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Were you ever able to shoot cast bullets in this rifle? Very curious as to whether you’ll be able to load into the rifling and if that helps with accuracy and compensates for the long freebore. I just gave up on an 1891 in 7.65 Argentine; even though it has an excellent bore the throat is so long that no bullet, cast or jacketed, will give reasonable accuracy. Time to re-purpose to a 7×57 using a Krieger.
- March 31, 2016 at 2:35 pm #26661GoodsteelKeymaster
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Quickload is not able to give perfect results. Many things effect the outcome of the data. For instance, that freebore may have an effect on velocity all by itself, but if your brass has larger internal capacity, speeds are lower. If your chamber was reamed large, speeds are lower.
The best thing to do is to tweak the program till it agrees with your rifle, then use it to make logical predictions about other powders/load combinations.
- April 2, 2016 at 2:17 am #26733
I got some shooting in today with H4895 and the Speer 270s.
Charge, Quickload, Actual
50gn, 2426fps, 2379fps
52gn, 2514fps, 2432fps
54gn, 2601fps, 2470fps
The H4895 seemed to have much less variance from Quickload than the other powders I’ve tried so far.
I think I’ll stay with the 52gn load. The shoulder is just starting to fireform completely and the primers all have rounded edges, so I think I’m still in the safe zone.
Now to get a bullet mold and see if she’ll shoot cast.
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