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Discussion Starter · #21 ·
Some topping off today. 185 PSPCL CCI-200
IMR-4064
56.5
2733
2736
2699
2732

57.0
2772
2749
2756
2737

57.5
2806
2821
2818
2817

58.0
2811
2845
2827
2849

BL-C(2)
62.5
2912
2913
2856
2900
 

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Discussion Starter · #22 · (Edited)
More shooting today. All the same factors,
IMR-4064
58.5gr
2898
2861
2869
2857

1" group

RE-17
65.0
2986
2979
2990
3000

65.5
3009
3006
3037
3007

Both of these RE-17 loads showed pressure signs on the case head, extractor marks etc. No trouble extracting though, will back off of this one. Was under an inch though.
 

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Discussion Starter · #23 ·
More loads today. All factors the same. 17 June 2018

Superformance
62.0
2582
2736
2549
2716

63.0
2769
2751
2768
2602

64.0
2638
2613
2621
2642

This was so inconsistent. Don't know if the density needs to be higher, cases were not up to the neck.

RE-17

63.5
2863
2864
2910
2899

64.0
2936
2943
2925
2954

Nice consistency, boomed well, no extraction issues, cases looked good.
 

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Remember that the 165 gr. .308" bullet equals the S.D. of a 170 gr. .323" bullet. If you're looking to hot rod the Gibbs, then the Speer 170 gr. at 50KCUP will be hard to beat, on both ends. What you lose in impact energy out younder, you'll pick back up in extra angular velocity. Angular V. doesn't degrade like your linear V, does. These old Speer's are work horses.



Speer's Big Eight Bullet is their 200 gr. number, but your Gibbs may not spin these quick enough, and their time in flight, will cost you accuracy in the woods, out past 250 yards. Shorter round nosed bullets hold their own out to about 250 yards. So there is a good reason for Federal to have kept that 175 gr. Round nosed soft point, in their 7mm Mauser, Classic Loading.


It also explains why the factories have kept their lower velocity 8mm Mauser ammo, going, which actually out penetrates in live game, compared to most of their higher velocity ammunition.


I never made a .375 cal. version of my 8mm Wildcat, because Speer's 285 gr. Spitzer wouldn't have worked worth a hoot in it. It would have either penciled through an animal's flesh, or just tumbled when it hit the first large bone.


So, if you're getting good neck tension with those 185's, find the most accurate, high density reloads, and go with them. IIRC, i shot a few Sierra Game Kings of 220 grs. in my wildcat 8mm and got 2670+fps, in my starting loads, out of my 29" long M-98's military stepped barrel. I pulled this one off in order to do more testing, and my new 8mm barrel will have the 1 in 9 twist, like the Mausers, but will have a tight, custom, chamber/throat. So I should get the same results with a 25 - 26 inch long barrel.


I will make the admission here that at 200 yards, it's been, Bang - Clang on metal silhouette gongs. And this was with a Red Dot sight mounted, forward, in the old military sight base. A little awkward, but still very effective, to the point of being monotonous. All of my wildcat accuracy tests were with Speer 200 gr. Mag. Tips, made for the Remmie Big Eight. Those Sierra Game Kings were only shot through my club's Oehler P - 35 Chrono for speed and S.D. values. We couldn't shoot for groups with it.
 

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Discussion Starter · #25 ·
Some topping off today. All factors the same
185 PSPCL Superformance
64.5
2672
2626
2669
2634

65.0
2657
2639
2689
2652

Giving up on this powder.

180gr SS North Fork bullet
R-17
63.0
2909
2901
2887
2913
Horrible group >4" THis gun has never shot over 2"

IMR-4064
57.0
2765
2775
2789
2777
1" group.
 

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I don't think that your particular rifle likes IMR 4064. Powley's says IMR 4350 or IMR 4831. The newer SSC IMR 4831 may be a good compromise between easy flowing powder and the correct burning rates. If the quicker 4064 would have been correct, Powley's powder computer would have picked it. Remember that all IMR powder grains have the same energy/weight. The different canister lots only have quicker or slower burning rates. So if you put any IMR powder into your wildcat case, up to it's neck, you have the exact same energy pushing the bullet out the end of the barrel. Too quick of a curve, and you blow up your gun. Too slow, and you only create a big fire ball, beyond your muzzle. Run your bullet weights through the Powley online computers and you'll see how lighter bullets need quicker powders. The 8 x 68S Schulers use 220 gr. bullets, effectively at around 2900 fps. To break 3000 fps, you need lighter bullets, and quicker?? powders. But IMR 4350 and IMR SSC 4831 may still give you higher velocities, from longer pressure curves.


If your super performance powder is the canister Hornady version of the trick powder mix, that they put into my 300 RCM loaded ammo, then it's the longer and higher pressure curve, which might be messing up your accuracy. My 300 RCM only has a 18 inch barrel seated in a full length R 77's forearm. And the pressures have already dropped off, resulting in much lower muzzle blasts. If you can borrow a rifle cradle, and put threads laying across your barrel, those Super Performance loads' nulls, might really surprise you.


Rocky G. wasn't building, stalking, wood's rifles. He lived, hunted, and designed hot rods to screech across stubble fields and nail Elk, 500 yards away, in the surrounding trees. And those Speer 170 gr. S.P.'s were about right for an Elk Rifle, having the military Mauser's one in 9.5" twist. IIRC, Rocky never made a 35 Gibbs, since his time in flight, out to 500 yards would have been too long.



I would never take a 500 yard shot with my 8mm Mag Wildcat rifle, as long as I only had open, or red dot sights, mounted.
Where I am comfortable, with "time in flight" bullet trajectories, is out to that 200 yards, with my Hot Core 200 gr. Spitzers, peeking through my Red Dot sight. But at 200 yards, I could do the same damage with a shorter, 200 gr. Round Nosed Soft Point, bullet. Out at 250 yards where the spitzers walk away from their round nosed brethren, my Red Dot sights, project too large of a light spot, onto the sides of a game animal, naturally camouflaged, by Mother Nature. And ditto that for my Nikon laser range finder. I can measure a rock's range at 900 yards, but I can't chew through one, either.
 

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Since H-414 is a ball powder equivalent of H-4350, H-414 might be a good powder to try. It also does better when sparked off by a magnum primer...

A
 

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Discussion Starter · #28 ·
Little shooting today. Fed 215M primers.

185 PSPCL Superformance powder
65.5gr
2747
2798
2832
2731

66.0
2886
2885
2901
2890

1" group

66.5
2919
2884
2920
2868

<1" group

196 Norma Vulcan 215M H4350

63.0
2744
2785
2740
2767

1 1/2" group

64.0
2798
2805
2818
2821

1" group
 

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You are right there with your Gibbs.

The Powley Predictions say to use 4831 or 4350, and you're right in his groove with these latest results. Rocky may have gotten higher tested velocities, but there's too much water under the bridge, for direct comparisons, IMO. Rocky's bullets changed when Remington came out with their Big Eight.
 

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Discussion Starter · #30 ·
I have some newly fire formed brass and loaded with IMR-4350 and H414 with the 185 PSPCL bullets. Also annealed them and used my new Frankford Arsenal tumbler with the stainless steel pins, wow, looks new. The new Timney trigger is a WINNER. Used it during fire forming. Love it.
 

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If I understood your earlier posts, you do have a commercial barrel?? If so, you have picked up about three inches over an old stepped Mauser military barrel, that has been re-chambered. This velocity loss, comes from the original chambers made for the old round nosed bullets, made prior to 1906.
 

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Discussion Starter · #33 · (Edited)
Realized I didn't input the H-414 data from 18 Aug 2018
185 PSPCL CCI-250
61.0
2690

62.0
2773

63.0
2821
2784
2812
2786

64.0
2864
2860
2907
2843
Just under an inch

65.0
2894
2980
2916
2917
5/8" group
 

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Discussion Starter · #34 · (Edited)
Some shooting today. WLP,
180 Nosler Ballistic Tip
63.0 RL-17
2902
2942
2933
2945

65.0 H-414
2915
2918
2902

180 Barnes Original
63.0 RL-17
2899
2917
2897
2903

65.0 H-414
2861
2892
2866
2838

200 Nosler Accubond
64.0 H-4350
2843
2849
2829

All shot at an inch.
 

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Expanded to .666 at the largest spot, weighed 132 Gr.
Joining the Barnes bullets copper club might help reduce that loss of projectile weight. My son in law’s older brother uses Barnes copper bullets in his Rem. Big Eight, exclusively. Now he’s on a replacement Douglas bbl. in his Rem. M 700 Magnum rifle. His first bbl. was ten inches of alligator skin ahead of the chamber. Today there are four really tough bullets made for this beast. When Rocky built these, the Speer 170 gr. Was about it.
 
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