Re17 / .243 Winchester / Nosler 55-Grain "SHOTS"

RiverRider · Nov 27, 2010

I commented in the Re17 thread about my experimentation with this combination but thought it better to not clutter that thread. I'll post what I've found here. The bullet is an overrun offering from Nosler. I think there may be some still available.

45.5 grains 3179 fps 3.0"
46.0 grains 3239 fps 2.5"
46.5 grains 3275 fps 3.0"
47.0 grains 3365 fps 3.5"
47.5 grains 3410 fps 3.5"
48.0 grains 3460 fps 1.6"
48.5 grains 2484 fps 2.2"
49.0 grains 3511 fps 3.0"
49.5 grains 3585 fps 1.1"
50.0 grains 3656 fps 1.14"
50.5 grains 3700 fps .93"
51.0 grains 3750 fps 1.66"

These figures are based on three-shot groups. I am fully aware that samples of three are not going to provide very reliable data, but I always say "take what you can get." SDs were fairly wild until the charge weight approached 49.0 grains, where they started coming in under 25.0. At 49.5 grains and higher, SDs are at or below 15.0.

I believe that the pressures encountered so far a quite mild based on the fact that Nosler data shows a 55-grain bullet being pushed to just shy of 4000 fps using Re15. It stands to reason that a slower powder can push the same bullet to equal or greater velocities safely IF enough of it can be stuffed in the case. The appearance of the primers on the fired cases also suggests the pressures are mild since there is little or no visible difference between the lowest charges and the highest charges.

I am looking at the 50.0- and 50.5-grain charges with the thought in mind that varying seating depth might bring it in, but the seating stem in my Redding .243 seater doesn't allow me to seat any deeper. It seats them fairly shallow as it is. I am going to take a look at using a spare seater stem from a .222 or .223 Remington die set to see if that will provide more flexibility without introducing excessive runout. I think I may be able to get up to 52.5 or 53.0 grains of Re17 under these bullets with little charge compression, but I have not decided one way or another on upping the charge.

If one of you guys wants to run Quick Load on this combination and post the results, it wouldn't hurt my feelings at all. This whole idea may be a bust, but if I can get accuracy at 3750 fps or better I am pretty sure it would be coming in at considerably lower pressures and that's not a bad thing.

DrMike · Nov 27, 2010

RR,

QuickLoad, with a Pmax of 62,000 psi, projects somewhat less powder.

Cartridge : .243 Win.
Bullet : .243, 55, Nosler BalSilTip 51030
Useable Case Capaci: 52.633 grain H2O = 3.417 cm³
Cartridge O.A.L. L6: 2.710 inch = 68.83 mm
Barrel Length : 22.0 inch = 558.8 mm
Powder : Alliant Reloder-17

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms

-20.0 77 39.20 2984 1088 30315 8880 85.9 1.187
-18.0 79 40.18 3059 1143 32412 9193 87.7 1.157
-16.0 81 41.16 3135 1200 34654 9496 89.3 1.127
-14.0 83 42.14 3211 1259 37052 9787 90.9 1.099
-12.0 85 43.12 3287 1319 39617 10064 92.3 1.064
-10.0 87 44.10 3363 1381 42362 10325 93.6 1.033
-08.0 89 45.08 3440 1445 45303 10569 94.9 1.001
-06.0 91 46.06 3516 1510 48452 10795 96.0 0.972
-04.0 92 47.04 3592 1575 51829 10999 97.0 0.943
-02.0 94 48.02 3667 1643 55452 11182 97.8 0.915 ! Near Maximum !
+00.0 96 49.00 3742 1711 59343 11342 98.5 0.888 ! Near Maximum !
+02.0 98 49.98 3817 1779 63525 11478 99.1 0.862 !DANGEROUS LOAD-DO NOT USE!
+04.0 100 50.96 3891 1849 68023 11587 99.5 0.836 !DANGEROUS LOAD-DO NOT USE!
+06.0 102 51.94 3964 1919 72870 11670 99.8 0.812 !DANGEROUS LOAD-DO NOT USE!
+08.0 104 52.92 4037 1990 78096 11724 100.0 0.789 !DANGEROUS LOAD-DO NOT USE!
+10.0 106 53.90 4108 2061 83737 11754 100.0 0.766 !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 96 49.00 3923 1880 70747 11117 100.0 0.822 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 96 49.00 3499 1495 49020 10907 92.2 0.971

RiverRider · Nov 27, 2010

Thanks for running that, DrMike.

I am surprised by and really wonder about the results, though. I notice a 150-200 fps discrepancy between observed and QL-predicted velocities, and that QL wants to stop you at about 250 fps LESS than what is published by Nosler using Re15. I can post a photo of the fired primers, but I don't think I could capture a difference photographically that I cannot even see. There were also no instances of sticky bolt lift or any other pressure signs. There is also a fairly smooth velocity increase curve for charge increases. Do you think that QL might just be wrong? Do you think, like I do, that since there is published data for Re15 yielding all the way up to nearly 4000 fps that Re17 should be able to safely do this provided enough powder can be gotten into the case?

DrMike · Nov 27, 2010

Bear in mind that every rifle is unique. If you worked up without obvious pressure signs, it can be a confidence builder. The QL data projects a chamber pressure of 68K psi at or near 51 grains, which is clearly excessive. Factors that may influence the pressure include such matters as lot-to-lot variation (you may have a lot that has as much as ten percent slower burn rate), case capacity (your case may be slightly larger than SAAMI standards) or a slow barrel (a slightly larger bore diameter). The QL maximum charge projected 3742 fps, and your data indicated approximately the same velocity with a charge of 51.0 grains. While you cannot make an exact extrapolation from velocity to pressure, it might indicate that you are not generating excessive pressure.

Were it my rifle, I'd probably continue to focus at a charge of 50.0 to 50.5, being aware of the possibility of pressure. I would perhaps prepare a test to verify that the SD is tight and that the velocity is within the parameters indicated by a safe pressure. Be careful when you purchase a new lot of RL17 to drop back at least five percent and work up just to verify that you are not generating excessive pressure.

RiverRider · Nov 27, 2010

That all makes sense to me. One thing I noticed is that you used a 55-Grain Ballistic Tip as an input. Maybe there is enough difference in that bullet and the Aussie bullet to make that much difference. These Nosler catalog number for these Aussie bullets is 45477. Since I have never played with QL, I have no idea how flexible it is. I have looked at the images of the 55-grain BT, though and it does appear to have considerably more bearing surface that the SHOTS" bullet does. Maybe that's a factor in this case.

JD338 · Nov 27, 2010

The Shots bullets arevery good quality bullets and accurate too! I loaded some 50 gr Shots in my 22-250 and shat a group that went .187"!

JD338

RiverRider · Nov 27, 2010

I am not surprised, JD. In my 20 years of reloading, Nosler bullets have always given me the best accuracy from my rifles. Only Hornady comes close, and that would be their .224" bullets. I know lots of folks like Sierra bullets, but I have never been able to get them to work for me.

Would anyone know where I could get a look at dimensional specifications on Nosler bullets? I am very strongly suspicious that these 6mm SHOTS have a really short bearing surface that is affecting pressure and velocity in variance with how a Ballistic Tip of the same weight would work.