.20 VIPER Load & Development Data

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RangerJoe

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Posted 1547756026 · Edited	Reply with quote #1

The first .20 Viper barrels (20", 24", and 26.5") are made and we will begin beta testing soon. The .20 Viper is the 3rd of our MONGOOSE line of wildcats (6mm Mongoose, .257 Ocelot, .20 Viper). It is based on a 5.56x45mm (.223 Rem) parent case, shortened slightly, with a sharp 40-degree shoulder and blown-out sidewalls to increase case capacity. Just like the 6mm Mongoose, the .20 Viper will require fire-forming to achieve it's final case dimensions and capacity. We are experimenting now with methods to form the brass for initial firing. Unlike the 6mm Mongoose which is initially formed in 1 step, the .20 Viper (and likely the .17 Stringer) will require 2 steps to form the initial case. Setting the shoulder back, changing it to 40-degrees, and necking down from .224 to .204 is too much for 1 process. We are looking at two different methods; both should work - and then we will recommend/offer the process we think is best. Our expectations are the Viper will outperform most, if not all, of the .20 caliber .222/.223-based wildcats on the market (e.g., 20 Tactical, 20 Practical, .20 VarTarg Turbo, etc.). It may even tickle the .204 Ruger, which is based on the larger .222 Rem Magnum case. We are hoping for MVs in the 4,250+ range with 32-grain bullets from a 24" barrel. That, my friends, is SMOKING HOT! Powders that I will initially be testing include: Alliant Varmint Win 748 Hodgdon CFE223 Hodgdon BL-C2 Hodgdon H322 Accurate 2520 Ramshot X-Term Ramshot TAC Accurate 2460 Accurate 2015 Hodgdon Varget Alliant 1200-R Norma 201 Alliant ARCOMP, 10X, and Hodgdon Benchmark are also likely good candidates, but I don't have any in my stash. As development progresses, we will create a separate ".20 Viper" topic under Mad Dog's Wildcats and post brass forming data, videos, and loading data just like we have for other cartridges. This should be a WILD RIDE! Stay tuned for more action to come... __________________ Sua Sponte \| Ranger Joe
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RIGGS68

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Posted 1548371086 · Edited	Reply with quote #2

Ok, my initial loads were very conservative so the performance may appear lackluster but it gives Joe and Bruce a little more insight- and it reduced the pucker factor for me. These were all fired using freshly formed brass. After fireforming, the capacity increase, on average, slightly over 1 grain. There were no malfunctions at all charges, the bolt locked back every time, and rounds fed flawlessly. 24 " SPR 32 NVG tipped H335 OAL 2.13 LC mixed 450 primer 25.3 3683 3698 3708 31 3744 25.6 3741 3735 3741 7 3749 25.9 3808 3757 3781 27 3798 26.2 3831 3833 3830 3 3827 26.5 3925 3894 3920 24 3943 32 NVG HP 8208 OAL 2.08 24.0 3469 3524 3481 38 3450 24.3 3584 3465 3507 66 3472 24.6 3511 3601 3584 66 3640 24.9 3642 3648 3625 34 3585 25.2 3704 3736 3709 24 3689 25.5 3754 3788 3766 19 3756
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RangerJoe

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Posted 1548388179	Reply with quote #3

Nice! Thanks Riggs. I got my barrel (20") and die this afternoon. I have the barrel mounted to a trued receiver - will slap on a scope and attempt some loads tomorrow and Saturday. __________________ Sua Sponte \| Ranger Joe
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RIGGS68

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Posted 1548389155 · Edited	Reply with quote #4

Quote: Originally Posted by RangerJoe Nice! Thanks Riggs. I got my barrel (20") and die this afternoon. I have the barrel mounted to a trued receiver - will slap on a scope and attempt some loads tomorrow and Saturday. Yeah, I am itching to get back out with it again and see what it will do with formed brass. Unfortunately, the weather here went south (temp-wise) so I doubt I will be able to gather more data this weekend.
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RangerJoe

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Posted 1548645655 · Edited	Reply with quote #5

20" 1:12 Light-weight (M16A1) profile barrel, rifle length gas system. NEW (non-fire-formed) LC 1x fired brass (RTL), CCI-41, W-748, Nosler 32gr VG HP Flatbase, 2.080" COAL, 5 rounds each: 26.0gr W-748 = 3,565 fps 26.5gr W-748 = 3,665 fps 27.0gr W-748 = 3,720 fps 27.5gr W-748 = 3,788 fps - added 02-FEB. This is about max load for non-fireformed brass. All loads cycled flawlessly... fed, ejected, bolt lock-back, etc. No pressure signs at all. Can't tell ejection pattern because I used catcher (can't afford to lose any of these!). Next loads will push the upper limits a bit... Note: 1) Edited to correct COAL. 2) These cases will be annealed before next resizing & firing. __________________ Sua Sponte \| Ranger Joe
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RangerJoe

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Posted 1548741486	Reply with quote #6

Currently I have Nosler 32gr VG HP-FB and 40gr Ballistic Tips to try. I just ordered Hornady 32gr & 40gr VMAX and Nosler 40gr tipped VGs. In my x40, the 110gr NVG-tipped is one of the most accurate and fasted bullets I've ever tested. __________________ Sua Sponte \| Ranger Joe
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RIGGS68

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Posted 1548794324 · Edited	Reply with quote #7

More load development data: (Magnetospeed chrono) 20 Viper 1:8 twist 24" SPR (.090 gas) LC mixed Fire formed brass 32 NVG -tipped 2.13 OAL 450 primer 10X 23.5 3559 3506 3566 64 3635 24.0 3710 3638 3656 47 3621 24.5 3805 3723 3767 41 3775 25.0 3871 3856 3876 24 3903 25.5 3887 3829 3894 32 3866 Benchmark 25.0 3735 3766 3764 28 3791 25.5 3817 3803 3799 19 3778 26.0 3936 3895 3917 20 3921 26.5 4025 4007 4010 12 4000 Rl7 (Cycled/fed but no BHO on empty mag all loadings) 23.0 3971 4019 23.5 4066 4103 4087 19 4074 24.0 4095 4181 24.5 4228 4238 Note: I ran out of FF brass so this was not 3 shot. Additionally, 24.0 and up had slight cratering of the primers.
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RangerJoe

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Posted 1548804187	Reply with quote #8

Congrats - first to break the 4k mark!! I'm chasing you... __________________ Sua Sponte \| Ranger Joe
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RangerJoe

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Posted 1549171460	Reply with quote #9

Made ~ 250 more Viper cases this weekend - that should last a few varmint exploding sessions! I only fire-formed another 15 - added that data to my OP above. I've about maxed out with W-748 for new (non-fire-formed) brass. Will move on to a fast powder next. __________________ Sua Sponte \| Ranger Joe
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Cabob

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Posted 1549224033	Reply with quote #10

Looks like 748 is working based on your speeds, just a little bulky and slow. Based on my experience with a .204 Ruger, 748 was just a little too slow in it as well (Out of a 26 inch tube, nonetheless.) I ended up settling on H335 for 32 gr. Vmax and TAC for 40 gr. Vmax. That factory Ruger will routinely shoot in the .1's with both bullets if I do my part. Out of the powders you have on hand, I think you should try CFE223 and TAC next. Wink, wink!
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RangerJoe

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Posted 1549236602 · Edited	Reply with quote #11

Again - these are only fireforming loads. The Viper gains a decent amount of capacity once blown out. My next batch of fireforming loads are being charged with Ramshot X-Term __________________ Sua Sponte \| Ranger Joe
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RIGGS68

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Posted 1549412184	Reply with quote #12

More data... 20 Viper 1:8 twist 42" SPR LC mixed Fire formed brass 32 NVG tipped 2.13 OAL 450 primer Benchmark 26.5 3952 3958 3949 10 3938 26.8 4007 3983 3992 13 3986 27.1 4029 4082 4046 30 4028 H335 26.5 3820 3931 3880 56 3840 26.8 3983 3943 3953 25 3955 27.1 4012 4065 4018 43 3978 27.4 4033 4101 4060 35 4048 AA2200 (avg) 24.0 3872 24.3 3872 24.6 3943 25.0 3963 TAC 24.0 3414 3523 3439 73 3382 24.5 3596 3596 3601 9 3612 25.0 3530 3656 3609 69 3685 25.5 3551 3670 3635 73 3685 26.0 3747 3775 3794 58 3860 26.5 3825 3832 3818 17 3798 All loadings cycled properly, locked back on an empty mag, and none exhibited signs of overpressure...onward and upward I guess.
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RangerJoe

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Posted 1549421190	Reply with quote #13

Very nice! What load did you select for your fireforming? I'm still playing with loading ladders to fireform my 250+ cases. It would be nice to have a reasonable accurate fast plinking load to be able to fireform with. __________________ Sua Sponte \| Ranger Joe
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RIGGS68

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Posted 1549422006 · Edited	Reply with quote #14

Quote: Originally Posted by RangerJoe Very nice! What load did you select for your fireforming? I'm still playing with loading ladders to fireform my 250+ cases. It would be nice to have a reasonable accurate fast plinking load to be able to fireform with. Right now I am running 26.5 H335, however, I had a "supply" of WC844 and some 34 grain VNE show up recently so I may switch to those. Hopefully, it will result in an inexpensive plinking/varmint load. Just trying to cover as many powders as possible...I will also transition to the 39 grainers on the next run.
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RangerJoe

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Posted 1549422109	Reply with quote #15

VNE ??? __________________ Sua Sponte \| Ranger Joe
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RIGGS68

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Posted 1549422406 · Edited	Reply with quote #16

Quote: Originally Posted by RangerJoe VNE ??? Varmint Nightmare Extreme..34 grain HP from Midsouth-they were on sale. https://www.midsouthshooterssupply.com/item/000042034/varmint-nightmare-x-treme-20-caliber-point204-diameter-34-grain-premium-flat-base-hp-500-count
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RangerJoe

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Posted 1549426045	Reply with quote #17

__________________ Sua Sponte \| Ranger Joe
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RangerJoe

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Posted 1549767591 · Edited	Reply with quote #18

Continuing the quest for accurate & fast fire-forming loads, I tested 4 loads with Ramshot X-Term today; still using Nosler 32gr VG-HP at 2.080 COAL and Wolf SRM primers. Temp ~ 60, RH ~ 45%, 7~20 winds at 7:30. 25.0gr X-Term: MVavg=3,710; 1.1" 5-shot group 25.3gr X-Term: MVavg=3,737; 0.95" 5-shot group 25.6gr X-Term: MVavg=3,823; 0.70" 5-shot group 25.9gr X-Term: MVavg=3,865; 0.95" 5-shot group All loads functioned perfectly with NO pressure signs. I'll run another few rungs up the ladder with X-Term as there is plenty of case capacity left, even at 25.9gr. __________________ Sua Sponte \| Ranger Joe
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Cabob

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Posted 1549770966 · Edited	Reply with quote #19


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RIGGS68

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Posted 1549772475	Reply with quote #20

Thanks RJ. This round is WAY more accurate and forgiving than I thought it would be.
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RIGGS68

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Posted 1550012535 · Edited	Reply with quote #21

Hopefully, I covered everything thus far...
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Cabob

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Posted 1550018955	Reply with quote #22

Looking good!
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RangerJoe

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Posted 1550019688 · Edited	Reply with quote #23

Nice! All my brass is LC-06, 1x fired, RTL (back as 5.56) before beginning the conversion to Viper. BC for the Nosler 32gr VG-HP is .131 (yuk) and VG-tipped is .204. I have more X-Term ladders ready to test. Thanks buddy! __________________ Sua Sponte \| Ranger Joe
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RIGGS68

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Posted 1550020854 · Edited	Reply with quote #24

Thanks Joe...updated to reflect information. Load data file moved to a newer post.
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RIGGS68

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Posted 1551224293 · Edited	Reply with quote #25

Data from today's 39 Sierra Blitzking ladders: (all are 3-shot) 20 Viper 24" 1:8 twist (SPR profile) LC mixed F/formed brass COAL: 2.215 Primer: 450 H335 25.0 3648 49 25.5 3675 21 26.0 3747 116 stopped here due to high SD Benchmark 24.0 3513 35 24.5 3572 16 25.0 3677 41 25.5 3768 31 26.0 3859 17 TAC 25.0 3540 44 25.5 3604 31 26.0 3703 15 26.5 3772 49 27.0 3841 19 8208 25.0 3621 16 25.5 3702 52 26.0 3754 14 26.5 3814 5 27.0 3935 30 primer pockets loose Additional fireforming data using WC844 - for reference only. 32 NVG-tipped COAL 2.13 LC-mixed 24.7 3469 51 25.0 3548 23 25.3 3614 24 25.6 3640 0 25.9 3680 14 26.2 3755 6 26.5 3785 9 The Excel load data file has been updated with this information. (Located in the prior post) I will continue to update it with load data that others post here -at least in the interim. I apologize for not adding any accuracy data, however, I find that a Magnetospeed strapped to the end of a barrel can have an impact on, at minimum POI. Additionally, unless indicated, all loadings were safe in my barrel...but you know the disclaimer.
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