KH_Outdoors
Well-Known Member
Absolutely!
Here is a pic for comparison:
from left - right
300 PRC/215 Hyb - 300 PRC - 33 SM/225 NAB
-
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338-300 PRC... Sherman Improved!
- Thread starter KH_Outdoors
- Start date
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Absolutely!
Here is a pic for comparison:
from left - right
300 PRC/215 Hyb - 300 PRC - 33 SM/225 NAB
KH_Outdoors
Well-Known Member
That's awful kind! I hope I don't "need" them. Picked up a few boxes while getting this project ready. Thank ya sir
KH_Outdoors
Well-Known Member
Making some progress here!
Getting some baselines for safe pressures and a general feel of what the rifle is going to like with the 225 Accubonds. Decided to start with H1000 & H4831sc, then moved on to H4350 & N555.
Speeds listed:
Notes: all charge weight ladders shot at 100 yards, same aiming point, 40-50 F, and noting point of impacts looking for charge weights landing close to one another along with general grouping size/shape.
H1000 - Definitely on the "slow burn" side of what this cartridge/bullet combo is going to run with. I didn't expect this to be the winner with 225's but just tested to be sure. Pretty large scattered group overall however showed potential with charge weights 81/82/83 & 86/87/88 gr clustering/touching. 84 & up is compressed which I'm not a fan of, less than that is slower than my goal. Zero pressure signs. Moving on to H4831sc.
H4831sc - Had high hopes for this powder, it has the most linear increase of speed accross the ladder and seems "just right" for case fill. However, very scattered grouping. Only two charge weights landing close to one another. 82/83 gr showing potential but with everything being so scattered I'm going one more step "faster" burn rate. No pressure signs still.
H4350 - I had a hunch this was going to be the standout. Research on the 338-300 PRC variants showed many shooters finding best results with H4350 even up to 250 gr projectiles. I fully expected to be able to hit some pressure signs stepping up to H4350 and I did, just a faint ejector mark starting on the top end. No heavy bolt, click, flat primer, or anything super concerning even up to 3000 fps. I did not want to push it further though with my goal being 2900+. Accuracy wise, hands down best promise of everything tested (see pic below). Charge weights 75/76/77 all clustering, then again 78/79/80 nearly in the same hole clustered. This is exactly what I look for during initial testing. I will go forward with H4350!
N555 - This is an interesting powder and I've always wanted to find a use for it. Not completely ruling it out yet but H4350 is the clear choice. The N555 showed some good promise on the low end of 76/77/78/79 all in one hole or within 1/2", so very forgiving around that 2800 fps mark. Good case fill being a bulkier powder than the H series, and known to be one of the most stable powders offered by Vhit. Just on the slower end, above 79 gr it just started scattering, so again H4350 is just the clear choice.
This is my preferred method of starting load work on my setups. I'm simply looking for components that are most likely to work well together and meet my goals. Always going with a "coarse to fine" approach, I've found that I can really waste a whole lot of time tinkering and tuning with the wrong combination otherwise. So rather than fine incremental ladders and fine seating depth tests I usually just start bullets approximately .030" off the lands and put charge weight ladders together with full 1 grain incremental changes (in large magnums, .5 in smaller cases). If I need to, or just want to do further testing I'll get into finer tuning of course. In the case of this exact combination, the next step is to go shoot groups at the charge weights of the combinations showing most promise.
Getting some baselines for safe pressures and a general feel of what the rifle is going to like with the 225 Accubonds. Decided to start with H1000 & H4831sc, then moved on to H4350 & N555.
Speeds listed:
Notes: all charge weight ladders shot at 100 yards, same aiming point, 40-50 F, and noting point of impacts looking for charge weights landing close to one another along with general grouping size/shape.
H1000 - Definitely on the "slow burn" side of what this cartridge/bullet combo is going to run with. I didn't expect this to be the winner with 225's but just tested to be sure. Pretty large scattered group overall however showed potential with charge weights 81/82/83 & 86/87/88 gr clustering/touching. 84 & up is compressed which I'm not a fan of, less than that is slower than my goal. Zero pressure signs. Moving on to H4831sc.
H4831sc - Had high hopes for this powder, it has the most linear increase of speed accross the ladder and seems "just right" for case fill. However, very scattered grouping. Only two charge weights landing close to one another. 82/83 gr showing potential but with everything being so scattered I'm going one more step "faster" burn rate. No pressure signs still.
H4350 - I had a hunch this was going to be the standout. Research on the 338-300 PRC variants showed many shooters finding best results with H4350 even up to 250 gr projectiles. I fully expected to be able to hit some pressure signs stepping up to H4350 and I did, just a faint ejector mark starting on the top end. No heavy bolt, click, flat primer, or anything super concerning even up to 3000 fps. I did not want to push it further though with my goal being 2900+. Accuracy wise, hands down best promise of everything tested (see pic below). Charge weights 75/76/77 all clustering, then again 78/79/80 nearly in the same hole clustered. This is exactly what I look for during initial testing. I will go forward with H4350!
N555 - This is an interesting powder and I've always wanted to find a use for it. Not completely ruling it out yet but H4350 is the clear choice. The N555 showed some good promise on the low end of 76/77/78/79 all in one hole or within 1/2", so very forgiving around that 2800 fps mark. Good case fill being a bulkier powder than the H series, and known to be one of the most stable powders offered by Vhit. Just on the slower end, above 79 gr it just started scattering, so again H4350 is just the clear choice.
This is my preferred method of starting load work on my setups. I'm simply looking for components that are most likely to work well together and meet my goals. Always going with a "coarse to fine" approach, I've found that I can really waste a whole lot of time tinkering and tuning with the wrong combination otherwise. So rather than fine incremental ladders and fine seating depth tests I usually just start bullets approximately .030" off the lands and put charge weight ladders together with full 1 grain incremental changes (in large magnums, .5 in smaller cases). If I need to, or just want to do further testing I'll get into finer tuning of course. In the case of this exact combination, the next step is to go shoot groups at the charge weights of the combinations showing most promise.
Very nice with no vertical.
What does the Sherman offer over the 338 RUM Imp. Running 300 gr Berger OTMs at 2800 fps w/91 grs of H1000. 27" barrel. 265 ABLRs feed through the Wyatt's box. What would a 338-300 PRC Sherman offer over the RUM? Would it not nearly be an identical cartridge to a 338 Edge or Rum Imp? Just curious? Forgive me if the question has already been answered. I have never run any of the Sherman cartridges. Interested though.
Pic is a 338 RUM IMP +P 35' shoulder w/ 300 berger sitting next to a 6.5x284 Norma
Pic is a 338 RUM IMP +P 35' shoulder w/ 300 berger sitting next to a 6.5x284 Norma
Magazine length and bullet impeding into case
KH_Outdoors
Well-Known Member
No problem!
To answer your question specifically, "What does it offer over the RUM?"
Less muzzle blast & recoil for the simplest explanation!
No doubt the RUM, RUM Imp, Edge, etc... all push bullets faster, yes 100%. They hold 10-20 gr more powder depending.
Building the fastest or biggest was not the goal. The goal being to have a mid sized 338 cartridge, in a packable handy configuration, to push modest weight bullets, at reasonable speeds . "For me", something with 80-85 gr powder case capacity is "just right", not too much, not too little.
The rifles intended use is for hard use in Alaska on big things. Emphasis on being handy inside 0-300 yards, yet still capable out to 500-600+ if needed.
I'll likely end up with a RUM at some point too, but it will be a different configuration for sure!
KH_Outdoors
Well-Known Member
This too is a consideration. The 33 Nos, 338-300 PRC, 33 SM all fall really nicely into the magazine setup I like!
For reference, the Hawkins Precision Hunter DBM has an internal mag length 3.770". Gives me lots of options!
300 Driver
Well-Known Member
My 230 ELDx speeds match yours…So far I've only tested with R26 out of my 24"bbl 33SM but here is what I have. I have only done one session of ladder testing and my chrono died, so data is spotty. I did not hit pressure signs with any of these and plan to test higher charges.
My COAL is 3.610 for all due to magazine. WLRM primers and Peterson brass.
CE 225 MTH
80gr no reading
80.5 2836fps
81gr 2871fps
81.5 2884fps
82-83gr no reading
Loaded up to 90gr(compressed) still to test
230 ELDx
83gr 2720fps
Loaded up to 88gr still to test
270 ELDx
72.5 - 80gr no reading, but no pressure signs. Good node at 79-80.
Loaded up to 83gr still to test
My COAL is 3.610 for all due to magazine. WLRM primers and Peterson brass.
CE 225 MTH
80gr no reading
80.5 2836fps
81gr 2871fps
81.5 2884fps
82-83gr no reading
Loaded up to 90gr(compressed) still to test
230 ELDx
83gr 2720fps
Loaded up to 88gr still to test
270 ELDx
72.5 - 80gr no reading, but no pressure signs. Good node at 79-80.
Loaded up to 83gr still to test
KH_Outdoors
Well-Known Member
Alright!! Some more 33 SM info coming out of the woodworks!
Feel free to update how it ends up shooting for you.
300 Driver
Well-Known Member
Will do! It takes me a while between range trips. Fireforming loads showed great accuracy, so I am hopeful.
Oh, and I rechambered a 338WM using the .312FB reamer, so very interested in your results as well!
Amazing looking rifle you have.
Oh, and I rechambered a 338WM using the .312FB reamer, so very interested in your results as well!
Amazing looking rifle you have.
KH_Outdoors
Well-Known Member
That will be neat to see how yours shoots the heavies in that longer FB reamer!
Thanks!
KH_Outdoors
Well-Known Member
Getting some work done here with 225 Accubonds + H4350.
Decided to dial in on that 2850-3000 fps range and shoot some groups starting at 76, and up to 80. Also loaded up a couple charge weights of H4831sc that showed some promise earlier "just because".
Pretty happy with what I'm seeing with H4350 still. Consistent Point Of Impact and good speeds. Definitely looking like it wants to shoot the upper end. I'm going to load up some more of 77/78/79/80 gr H4350 and see which charge repeats. Seems like nearly all charge weights shot same POI shots 1&2, but #3 drifts off, then 80 gr really drilled
.
Velocities: 3-shot average
H4350
75 - Fouler group
76 - 2835
77 - 2899
78 - 2926
79 - 2974
80 - 3004
H4831sc
82 - Fouler group
82 - 2842
83 - 2898
Decided to dial in on that 2850-3000 fps range and shoot some groups starting at 76, and up to 80. Also loaded up a couple charge weights of H4831sc that showed some promise earlier "just because".
Pretty happy with what I'm seeing with H4350 still. Consistent Point Of Impact and good speeds. Definitely looking like it wants to shoot the upper end. I'm going to load up some more of 77/78/79/80 gr H4350 and see which charge repeats. Seems like nearly all charge weights shot same POI shots 1&2, but #3 drifts off, then 80 gr really drilled
.Velocities: 3-shot average
H4350
75 - Fouler group
76 - 2835
77 - 2899
78 - 2926
79 - 2974
80 - 3004
H4831sc
82 - Fouler group
82 - 2842
83 - 2898
Last edited:
KH_Outdoors
Well-Known Member
Checked 77/78/79/80 gr again and nearly identical results as before. Load development with 225 Accubonds + H4350 done 
, couldn't ask for much better than that!!
Next up I'm going to do a little testing with the new McGuire Ballistics 338's! Somewhere along the lines I need to test some 250 SMK's too. The hard work is done, so now I can go tinker a little bit more "just because"
.
, couldn't ask for much better than that!!Next up I'm going to do a little testing with the new McGuire Ballistics 338's! Somewhere along the lines I need to test some 250 SMK's too. The hard work is done, so now I can go tinker a little bit more "just because"
.
