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My 338 Sherman Shortmag
- Thread starter ruby76
- Start date
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I finally have some data to add for the 338ss. Sorta funny that this build was supposed to be done in July, to give me time to prep for hunting. 10 days left in the season and I finally have a load.
Thank you to everyone who has been testing and posting before. It has been very helpful and was a great start!
I do need to add one caveat to this data. I changed how I seat my primers after most of the pressure testing was done. This seems to have affected velocity, by bumping the loads up by 25-50fps from what I was getting previously at the same powder charge and I also saw max pressure at lower powder charge as a result. So as always, use this data with caution.
As I have been sorta rushing to get a hunting load ready for my last hunt of the season, I didnt have time to go back and reconfirm any of the testing or do seating depth or accuracy testing. I'll fine tune these loads. Also interested to see if the pressure level changes once I have more twice fired brass, as in the limited testing I did in twice fired brass, it seemed to hold more pressure.
Gun Details
22" barrel
2.102" to the lands (I asked that it be throated an additional 0.100" over the standard reamer)
Goal of this gun/bullet combo is a 650 yard Elk round. 1000yard deer round. My personal limit is well below that and most of my hunting is done in timber, so I decided to take the velocity hit, to have a shorter, handier gun.
All loads were in once fired ADG brass, 215m primer, neck diameter set with a .336 mandrel, powder loaded with a 4" drop tube.
213 Hammer Hunter, 2.090" CBTO
Varget
56.0 grains. 2622fps
57.0 2663
58.0 2729
59.0 2768
60.0 2808
61.0 2850
62.0 2891 slightest flattening of primer...
H4895
56.0grains 2734fps
57.0 2806
58.0 2887 mild flatten of primer
59.0 2924 mild primer/dull ejector/2 finger bolt
60.0 didnt shoot
IMR 8028XBR
55.0grains 2709fps
56.0 2758
57.0 2794
58.0 2860
58.5 2864 no pressure signs, more room in case
Figured I'd hit pressure at 59.0, so didn't load higher. Given the flat velocity between 58.0 and 58.5, I probably wouldnt expect too much more velocity without pressure, so unlikely to test higher.
At this point I changed from using my Forster CoAx to seat primers, which were setting the primers .001" off the bottom of the primer pockets to a 21st Century primer seater. I foolishly thought I might save money by using the Press. It's always been good to me with my other cartridges, but the ADG brass has .002" deeper pockets then my various other Norma and Lapua brass, which resulted in no crush. Which I was about to find out pooched most of my data. Now I also hit about 120 rounds thru the barrel, so maybe that was the reason for the jump in speed???
Tried a couple seating depth tests, and shot for groups with 62.0 of Varget and 57.8 of H4895. Everything I loaded was over pressure. And giving 0.5 to 1.0 grain faster velocities then what was shown in the pressure testing phase. But the Varget gave me a 0.24MOA 3 shot group.
I only had 50 bullets to work with and no way of getting more, so I had to limit further testing.
I was hoping for 2900fps and I almost had that with Varget at 61.0 grains at 2894, but that was at the very bottom of a narrow accuracy node, drop off even 10fps and the POI changed by 1" vertical. Add more powder to get deeper into the node and I was getting closer to pressure then I'd like.
Settled on H4895 at 57.0 grains, yielded a 0.5MOA group and 2825fps.
I'd like to explore these 3 powders more and do a proper ladder test with smaller increments between powder charges, but I simply ran out of bullets and time. But my guess is that alot closer to 2875 is achievable with more accuracy.
If I can shake the flu that I've had for the past two weeks I'll hunt most of the last week of the season. Here's hoping I can pull it off.
Thank you to everyone who has been testing and posting before. It has been very helpful and was a great start!
I do need to add one caveat to this data. I changed how I seat my primers after most of the pressure testing was done. This seems to have affected velocity, by bumping the loads up by 25-50fps from what I was getting previously at the same powder charge and I also saw max pressure at lower powder charge as a result. So as always, use this data with caution.
As I have been sorta rushing to get a hunting load ready for my last hunt of the season, I didnt have time to go back and reconfirm any of the testing or do seating depth or accuracy testing. I'll fine tune these loads. Also interested to see if the pressure level changes once I have more twice fired brass, as in the limited testing I did in twice fired brass, it seemed to hold more pressure.
Gun Details
22" barrel
2.102" to the lands (I asked that it be throated an additional 0.100" over the standard reamer)
Goal of this gun/bullet combo is a 650 yard Elk round. 1000yard deer round. My personal limit is well below that and most of my hunting is done in timber, so I decided to take the velocity hit, to have a shorter, handier gun.
All loads were in once fired ADG brass, 215m primer, neck diameter set with a .336 mandrel, powder loaded with a 4" drop tube.
213 Hammer Hunter, 2.090" CBTO
Varget
56.0 grains. 2622fps
57.0 2663
58.0 2729
59.0 2768
60.0 2808
61.0 2850
62.0 2891 slightest flattening of primer...
H4895
56.0grains 2734fps
57.0 2806
58.0 2887 mild flatten of primer
59.0 2924 mild primer/dull ejector/2 finger bolt
60.0 didnt shoot
IMR 8028XBR
55.0grains 2709fps
56.0 2758
57.0 2794
58.0 2860
58.5 2864 no pressure signs, more room in case
Figured I'd hit pressure at 59.0, so didn't load higher. Given the flat velocity between 58.0 and 58.5, I probably wouldnt expect too much more velocity without pressure, so unlikely to test higher.
At this point I changed from using my Forster CoAx to seat primers, which were setting the primers .001" off the bottom of the primer pockets to a 21st Century primer seater. I foolishly thought I might save money by using the Press. It's always been good to me with my other cartridges, but the ADG brass has .002" deeper pockets then my various other Norma and Lapua brass, which resulted in no crush. Which I was about to find out pooched most of my data. Now I also hit about 120 rounds thru the barrel, so maybe that was the reason for the jump in speed???
Tried a couple seating depth tests, and shot for groups with 62.0 of Varget and 57.8 of H4895. Everything I loaded was over pressure. And giving 0.5 to 1.0 grain faster velocities then what was shown in the pressure testing phase. But the Varget gave me a 0.24MOA 3 shot group.
I only had 50 bullets to work with and no way of getting more, so I had to limit further testing.
I was hoping for 2900fps and I almost had that with Varget at 61.0 grains at 2894, but that was at the very bottom of a narrow accuracy node, drop off even 10fps and the POI changed by 1" vertical. Add more powder to get deeper into the node and I was getting closer to pressure then I'd like.
Settled on H4895 at 57.0 grains, yielded a 0.5MOA group and 2825fps.
I'd like to explore these 3 powders more and do a proper ladder test with smaller increments between powder charges, but I simply ran out of bullets and time. But my guess is that alot closer to 2875 is achievable with more accuracy.
If I can shake the flu that I've had for the past two weeks I'll hunt most of the last week of the season. Here's hoping I can pull it off.
Last edited:
ramrod79
Well-Known Member
Good write up thank you for all the good info I think 2875 with a short barrel is excellent results for that bullet
ramrod79
Well-Known Member
So today with only 3 weeks until my late season Bull Elk tag zone opens I figured I would just double check Rifle after a rigorous hunting season.
I shot a 2 shot verification off hood of truck using a soft bag @ 580 yards with the 230ELDX aim point top of the black spot on trees where my finger is there was a 5-8mph cross wind that I did not correct for but as you can see it was not needed. I think that I should be good to go for late season elk.
I shot a 2 shot verification off hood of truck using a soft bag @ 580 yards with the 230ELDX aim point top of the black spot on trees where my finger is there was a 5-8mph cross wind that I did not correct for but as you can see it was not needed. I think that I should be good to go for late season elk.
WiscGunner
Well-Known Member
- Joined
- Aug 2, 2016
- Messages
- 321
What sorta BC are you finding with the longer nose version 236 HH's?
I haven't shot it yet. I believe further back in this post there was quite a bit of data for the load that was developed by Hammer Bullets. During my conversations with Steve from Hammer, I made a note that they expected it to be closer to a G7 of .295. I dont know if that has been confirmed.
David Lindler
Well-Known Member
260 grain 338 hammer exit splatter st 2816 fps.. chunks of lungs on the ground.That is flat cookin' doc! Thats both ends of the spectrum with the Sherman brass now with the same result. (6.5SST to 338 SS) That ADG brass is TOUGH!
I really think that there are 2 or 3 powders that may give more velocity than W760, if you can believe that! I think Superformance for sure but it has lousy temp stability. I also think RL17, H100V, and maybe N560 might light it up.
I guy in Wy. just got his together on a long action and we throated it looooooong for the 260 Hammer. Can't wait to see what his does!
I think even the standard throat reamer is a ligit 2800+ rifle with a 250 Berger.
We need to figure out a way for Aaron to get some brass
Three shot group st 100 with 260 grain hammer.
Attachments
What grain and powder are you using for the 260 hammers? 338ss or 338 max?
ramrod79
Well-Known Member
T
tagging in on this one I hole it's SS
ruby76
Well-Known Member
Updated rifle pic with a KRG bravo stock and Zeiss Conquest V4 in a 6-24. Loading H4350 lately, maxing out case capacity at 62 grains with a 250 berger, around 2730 fps. I may try a drop tube to pack a bit more in as I haven't quite yet pressured out. Keep in mind I have the standard throat and fairly short overall length. I've tested varget again and in my rifle and I've concluded it's too fast and pressuring out too soon. I may need to look at some throating but for now I'll try a couple different powders.
ramrod79
Well-Known Member
Wow that sure looks different now
David Lindler
Well-Known Member
What is the recoil like on this? with and without the brake? 338SS?
I'd like to put together a Sherman. I have a Rem 700 LA and and a TL Hunter LA (std bolt faces) sitting here.
