30 Sherman Magnum 20” Build

CA48

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Joined
Nov 18, 2009
Messages
1,198
Location
Texas
After carrying around long barreled heavy rifles for years I wanted something that hit hard and was more packable for mountain hunts. I’ve always been a big fan of the versatility of .30 cals. After years of shooting game with cartridges from .17cal-.338 I favor bigger calibers even for deer sized game. Just less margin for error at the cost of more recoil. With this build I wanted to try for a do it all rifle, medium weight with the larger cartridge, and something that gets preference every time I go hunting with the exception of varmints. All I’ve done so far is a pressure test with 215 bergers, ADG brass from Rich, N570, and shot some factory PRC ammo. I will be posting results over time as I test multiple powders and bullet combinations. Imr 8133, H1000, Ramshot LRT, 230 Berger, 220 Berger, and something from the Hammer line. I will post rifle weight when I get a chance to put it on the scale. As always a big shout out to Rich for his help and all his efforts to create innovative cartridges.

Rifle Specs
Rem 700
Ti FPA
20” Proof CF
Stock is from an original Proof Tac II rifle
Murphy Ti base 20MOA
NXS 5-22x56 for now
Seekins Rings
Badger knob
Jewel trigger
Hawkins BM
Terminator T3/Suppressor


Pressure Test done with a single piece of brass
55*
COAL 3.722 +.005”
N570
ADG brass
Fed215M
215 berger
NT .001

84 2881 2 Firings on brass
85 2917 3X
86 2946 4X, fired case could easily be chambered again
87 2983 5X, clicker, primer was still round
88 2988 6X, Bolt lift, flattened primer, no ej mark not even a faint one. Hot load though!

These are case web measurements just above the extractor cut measured after the case was sized on each firing.

virgin unfired .529”
83gr 1X .5315”
84gr 2X .532” 2881fps
85gr 3X .532” 2917
86gr 4X .532” 2946
87gr 5X .532” 2983
88gr 6X .5325” 2986

Velocity is right where I expected it with the proof. I hope to find my load around 85-86gr with the 215 bergers.

Velocity Data was measured with a Magneto Speed. I recorded one shot from factory 300PRC ammo with the 212gr ELD-X at 2626fps.

I will continue to update this thread as I test and gather data. Rifle has 21 shots through it as of now.

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phorwath

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Joined
Apr 4, 2005
Messages
7,276
Location
Alaska

At what powder charge do you start compressing powder while seating bullets? I start compressing powder @ 85.5gr N570.
I start getting some wonky MV's past 84gr, shooting 205gr copper monolithic bullets. Inconsistent powder ignition with CCI 250s. I may switch to Fed 215 primers with next batch of loads and see if MV becomes more consistent.
 

tim_w

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Joined
Mar 25, 2008
Messages
566
What about the newer 565? It seems to be right in between 560 & 570. Its suppose to have same bulk density and energy of those two just burn rate between the two. That should achieve velocity at an earlier peak pressure at a lower charge weight comparitively to 570. I wish they could make the 500 series with the bulk density of RL26.
 

phorwath

Well-Known Member
Joined
Apr 4, 2005
Messages
7,276
Location
Alaska
What about the newer 565? It seems to be right in between 560 & 570. Its suppose to have same bulk density and energy of those two just burn rate between the two. That should achieve velocity at an earlier peak pressure at a lower charge weight comparitively to 570. I wish they could make the 500 series with the bulk density of RL26.
Tim,
Are you referring to N565..., or N568? I've read recently of a new Vhitavuori N568... to be released in the 2nd quarter 2021.

 
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