.375 Norma

Swamplord

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I'm definitely into renting the reamer, would like to hear how you are doing with loads and a little on accuracy first though. Looks like a real winner here.

Awesome.

You may like what I have in this update on the 375 PRO.......

Did some shooting on Saturday with 300 gr Swift A Frame and 300 gr Nosler Accubond bullets loaded with 90.0 gr of H4350

also did an incremental load workup with 320 gr Cutting Edge bullets with Reloder 22 and IMR 7828 powders........

Brass is the 423 Dakota necked down and fire formed with 20 gr Blue Dot & cream of wheat then run through a full length die to size neck down then through a mandrel for neck turning, necks were turned to OD of .402" when bullet is seated for a .004" clearance in chamber (chamber neck is .406")

All bullets were coated with WS2 Tungsten Disulfide (Danzac)
Federal 215 Magnum primers in all loads
27" 12 twist Brux barrel
Riflescope is a Sightron SII Blue Sky 3-12x42mm , set at 12 x for all shooting....
Magnetospeed Chronograph was on at all times during shooting to record all velocities.... contrary to other forum members reports that the Magnetospeed unit impacted group size negatively, I found no such problem !
Temp at 35 degrees and breezy, I kept ammo in truck with heater on and temp at 70 degrees, taking out 1 round at a time to fire withing a few seconds......

Shooting was conducted at 103 yards due to it being the max distance at shooting location....

.......
 

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Swamplord

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300 gr Nosler Accubond bullets (coated with WS2)
COAL 3.470" Ogive oal 2.775" (.043" bullet jump)

90.0 gr H-4350

2951 fps
2956
2927
3 shot group at .974" (first target)

2965 fps
2958
2920
3 shot group at 1.075" (2nd target)


(need to mess with seating dept to fine tune load and shrink groups)


.......................
 

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Swamplord

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Next up is the 300 gr Swift A Frame (coated with WS2)
COAL 3.255" Ogive oal 2.775" (.048" bullet jump)

90.0 gr H-4350

2935 fps
2948
2963
3 shot group at .483" (1st target)


2962 fps
2939
2937
3 shot group at .314" (on left of 2nd target)

2956 fps
2951
2939
3 shot group at .573" ( on right of 2nd target)

I had 6 targets on my target board, I used up the top two for sighting in and center two for the Accubond bullets, bottom left target for the first A Frame bullet group, leaving me with one target , by this time the barrel was getting pretty hot and I wanted to keep shooting to see how it does so I lined up the crosshairs with the targets left upper quarter vertical and horizontal black edges and fired 3 shots then did the same for the right side, now the barrel was blazing hot ! the groups were pretty darn good for a hot barrel,

.......
 

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Swamplord

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320 gr Cutting Edge MTH bullets (coated with WS2)
COAL 3.626" Ogive oal 2.697" (.023" bullet jump)
IMR 7828 powder

this was an incremental load workup from 80.0 gr to 88.0 gr, I had not used this bullet and powder combo yet and wanted to start low to generate a known velocity table ....

80.0 gr 2340 fps
81.0 gr 2366
82.0 gr 2376
83.0 gr 2449
83.5 gr 2454

84.0 gr 2458 fps
84.5 gr 2496
85.0 gr 2530
3 shot group at .745" (1st target)

85.5 gr 2529 fps
86.0 gr 2521
86.5 gr 2561
3 shot group at .650" (2nd target)

87.0 gr 2585 fps
87.5 gr 2598
88.0 gr 2642
3 shot group at .250" (3rd target

(ran out of loads at 88.0 gr of IMR 7828)

After shooting the A Frames and Accubonds I let the barrel cool completely but did not clean it, from previous experience with Tungsten Disulfide, barrel tends to start shooting better with more rounds thru it, I have gone up to 100 rnds in my 7.82 Warbird and 300 RUM without cleaning with no ill effect on accuracy... I did not adjust the cross hairs on the scope after the earlier shooting and was not surprised at the completely different point of impact between the jacketed and solid HP turned bullets.....
as the velocity went up the groups shrank with zero pressure signs on brass and bolt lift was nice and light, extraction was smooth indicating that the WS2 coating was doing it's job in keeping pressures in check, I will keep going in half grain increments until I reach pressures just to record known max load data with IMR 7828 and the 320 CE MTH bullets......


......
 

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Swamplord

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Joined
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Location
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320 gr Cutting Edge MTH bullets (coated with WS2)
COAL 3.626" Ogive oal 2.697" (.023" bullet jump)
Alliant Reloder 22 powder

this was also an incremental load workup from 80.0 gr to 88.0 gr of RL 22 for the same reasons stated earlier......

80.0 gr 2309 fps
81.0 gr 2378
82.0 gr 2428
82.5 gr 2417
83.0 gr 2439
83.5 gr 2480

84.0 gr 2481 fps
84.5 gr 2513
85.0 gr 2487
3 shot group at .890" (1st target)

85.5 gr 2536 fps
86.0 gr 2564
86.5 gr 2575
3 shot group at .450" (2nd target)

87.0 gr 2577 fps
87.5 gr 2601
88.0 gr 2628
3 shot group at .400" (3rd target)

(ran out of loads at 88.0 gr of RL 22)

the exact same results were obtained with RL 22 as before with IMR 7828... as velocity went up the groups shrank with absolutely no signs of pressure with room to work up to higher velocities.. Reloder 22 impressed me due to the fact that all the groups produced nice triangular group patterns as they shrank with velocity increase.....
now that I have fully fireformed brass I have a slight increase in case capacity and a better fit in chamber after partial neck sizing.... I only have 20 of the 320 gr CE bullets left and will load them up and save for my black/brown bear hunting trip in a couple of weeks...

coming up next..... loads with Barnes 250 gr TTSX BT and 300 gr TSX FB.... (if I can find the time, going back to work after a month off.... tweaking on brass and burning powder...)
 

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Last edited:

LeddSlinger

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Really wish Swamplord would have followed thru on this thread about the 375 Norma Mag Improved. Would have really liked to see where he got with speed and accuracy using different powders.

Hoping to revive it and get more info on this round. With all the new powders on the market these days from VV and Alliant, I think this round could be a really impressive long range performer with amazing knockdown power on big game. I am thinking about building one on a custom action platform with a top shelf long range optic
 
Last edited:

RH300UM

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Really wish Swamplord would have followed thru on this thread about the 375 Norma Mag Improved. Would have really liked to see where he got with speed and accuracy using different powders.

Hoping to revive it and get more info on this round. With all the new powders on the market these days from VV and Alliant, I think this round could be a really impressive long range performer with amazing knockdown power on big game. I am thinking about building one on a custom action platform with a top shelf long range optic
I ended up building a 375 RBH (338 nm necked up and improved). I built mine for a Guide rifle duties and not long range. 22 inch proof barrel. Pushing 270 Hammers @ 3000 fps over n555. It is 1.5 grains below max load.
56A11948-1F0E-4440-BD7A-4D97066F0DAC.jpeg
9F3F27C4-9AC6-4961-95B9-487A27B44A28.jpeg

RBROS designed the round and built the rifles for me
 

LeddSlinger

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I ended up building a 375 RBH (338 nm necked up and improved). I built mine for a Guide rifle duties and not long range. 22 inch proof barrel. Pushing 270 Hammers @ 3000 fps over n555. It is 1.5 grains below max load. View attachment 312407View attachment 312405
RBROS designed the round and built the rifles for me
Nice! I bet that big bore hits hard. Thanks for sharing :)
 

Swamplord

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Messages
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Location
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Really wish Swamplord would have followed thru on this thread about the 375 Norma Mag Improved. Would have really liked to see where he got with speed and accuracy using different powders.

Hoping to revive it and get more info on this round. With all the new powders on the market these days from VV and Alliant, I think this round could be a really impressive long range performer with amazing knockdown power on big game. I am thinking about building one on a custom action platform with a top shelf long range optic

Oh but I did follow through ... in fact I did 3 different versions total in 375 cal and settled on the 375 Skuldryl with the most capacity .... also did it in .408 cal

just got tired of the jackwagons telling me how I shouldn't do it on a Rem 700 so I quit posting about my builds and accumulated data

....
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Swamplord

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Messages
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Location
Alaska
I had custom bullets made in 408 cal by Cutting Edge & Badlands for my 400 Skuldryl project, had Rock Creek spin up an 8 tw barrel, cool stuff to mess with , puts a lot of "dangerous game" cartridges to shame, lol

....
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LeddSlinger

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LRH Team Member
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Messages
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Location
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Oh but I did follow through ... in fact I did 3 different versions total in 375 cal and settled on the 375 Skuldryl with the most capacity .... also did it in .408 cal

just got tired of the jackwagons telling me how I shouldn't do it on a Rem 700 so I quit posting about my builds and accumulated data

....
View attachment 317886View attachment 317887
Thanks. Yeah you shouldn’t have built that on a 700...Lol! ;)
 

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