Hey Boomy,

I thought you might want a flanged version of your .423/.375 to go with your belted version so here it is.

The Chamber:
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The Cartridge:
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I’d think this could be built on the same frame as the standard .375 Fl. Mag. N.E.? If it so ought to make a nice light trim free swinging DR. Also would make an equally nice single shot.

I did run QL for the .423/.375 Fl. Mag N.E. with its 47137psi Pmax (MAP) and was able to run the 2150fps – 2200fps with a 24” barrel length using the 400gr CEB Safari Solid, the slightly shorter 387 GSC FN was worth another 50fps – 75fps at the same pressure level. I ran the matching 375gr CEB Safari Raptor which easily produced 2300fps. I did not run any of the lighter weight CEB brass bullets nor did I run any C&C bullets.

For a longer ranging copper HP spitzer bullet, I ran the 320gr CEB MTH Multi-Band and the 320 GSC HV, both easily produced 2500fps at identical pressure.

I reckon one would have to identify the optimum loading since it’s primarily for a DR. So what to use? Not sure so since it has a 24” barrel, and the barrels will be thin compared to a bolt or single-shot rifle I’ll try “barrel time” which for the above Pmax settles down to Node 7 or 1.434ms. And yes I played with 25” and 26” barrel lengths but both stayed with Node 7 and there was no performance gain. Now juggling through the powder table for a 100% or slightly compressed loading with 100% powder burn, or at least as close as possible, resulted in the following powders being identified:
24” Barrel = 1.434ms BT
BT = Barrel Time
FR = Fill Rate
BR = Burn Rate
Primary Results = FR
Vihtavuori N150 – 71.76grs @ 98.8% FR = 2178fps & 4213ft-lbs @ 44387psi = 99.77% BR
Hodgdon Hybrid 100V – 75.49grs @ 101.4% FR = 2201fps & 4301ft-lbs @ 42356psi = 98.84% BR
Alliant RL-17 – 75.6grs @ 93.6% FR = 2246fps & 4480ft-lbs @ 41370psi = 98.8% BR
Accurate 4350 – 76.83grs @ 99.8% FR = 2247fps & 4483ft-lbs @ 43432psi = 97.7% BR
Vihtavuori N550 – 75.48grs @ 96.0%FR = 2231fps & 4420ft-lbs @ 43078psi = 97.3% BR
Norma 204 – 77.63grs @ 97.7%FR = 2183fps & 4234ft-lbs @ 42561psi = 91.3% BR
ADI AR2209 – 78.02grs @ 101.9% FR = 2185fps & 4240ft-lbs @ 42213psi = 90.94% BR
Primary Results = BR
Accurate 4064 – 70.35grs @ 93.4% FR = 2234fps & 4434ft-lbs @ 46760psi = 100% BR
Norma 202 – 65.8grs @ 86.9% FR = 2180fps & 4220ft-lbs @ 44973psi = 100% BR
Vihtavuori N135 – 66.57grs @ 95.4%FR = 2169fps & 4180ft-lbs @ 45245psi = 100.0% BR
ADI AR2219 – 61.4grs @ 77.3%FR = 2159fps & 4140ft-lbs @ 44367psi = 100% BR
Hodgdon H322 – 61.4grs @ 82.2% FR = 2159fps & 4140ft-lbs @ 44367psi = 100% BR

Anyway, I’m not sure how important this BT stuff is to DRs considering the odd manner in which they’re regulated. Perhaps it’ll make regulation easier. Perhaps it means nothing.

Those Numbers look pretty good. I like the idea of this on a light double the size of a 375 flanged with a second set of barrels. 375 flanged for PG and 404-375 flanged for tougher animals. Thanks

I don't know that the 375 Flanged would work any better on PG than the 320gr CEB MTH MB or the 320gr GSC HV bullets from the 423/375 Flanged. Maybe not... Maybe so...

Hum...just ran the numbers for a 250gr Barnes TTSX in the 375 Flanged and its looking about 2500fps - same as the 320gr .423 CEB and GSC... So likely not...

quote:

Originally posted by boom stick:
OK...

Being that we are bastardizing two English carts together 404-375 does not seem that bad.

I like your thinking.

Did anyone get on the bandwagon with this project? After doing a ton of reading, I'm wondering... what was the final decision on reamers, a single piece rough and finish reamer? OR, just the finish pilot reamer to go from 375H&H to .423?? Did CH4D ever make the dies?? I love the .423 caliber, have a bunch of bullets... 404 JEffery, 404 Ruger (in the works), would really like to see a 404-375H&H in my safe.

I had one built. I have the reamers, a 375 H&H and the Neck & Throat reamer.

Glad you made one. A few questions if you please... How are you liking yours? Any comments on recoil? Feeding? What loads and velocities are you getting? Rebore or rebarrel? Any advice you would give to someone trying to make one? can you post loaded rounds? Thanks!

quote:

Originally posted by Jgrabow6493:
I had one built. I have the reamers, a 375 H&H and the Neck & Throat reamer.

I like it. I used a Weatherby Southgate Mauser for the build. I got it for a good price because the rifle had a repaired and refinished stock that I later sold. I used a NOS Browning FN Mauser stock I bought from Western Gun Parts Ltd., Canada to restock the rifle. Re-barreled with a 423-14 CM 6-groove #5 contour Lilja barrel. No issues with feeding so far. Scoped rifle weighs 9 lb 6 oz unloaded and no sling. I use H4895 and Varget and get 2260 to 2300 fps @ 15' from the muzzle. The last reloads are showing case head separation???? Recoil is what you would expect from a rifle of the weight and caliber. I purchased a separate "neck and throating reamer with a removable pilot for D'Arcy Echols' version of the 404-375 H&H" and a "standard 375 H&H reamer" from Hugh Henriksen, Henriksen Tool Co Inc. My gunsmith asked why I didn't have just one reamer made. That would be the only change I would make. The picture shows a 404-375 H&H round next to a 375 H&H round.

Very Nice!

Love the look of this round. How many reloads are you getting before signs of case head separation? Would you be willing to rent out the reamer (pair)??

Thank you. I mentioned the feeding because the design is based off of the original 375 H&H case taper which is renowned for feeding an extraction so if it was based on a 375 H&H donor gun, the feeding should be slick with zero to no smithing needed to work as a functioning DG rifle. I am glad you are enjoying yours. Did you do the 2.8” case length or 2.85”? With traditionally shorter tip to canalure 404 bullets, the 2.85” case would be fine IMHO. 2300 ft./s was my target top velocity for this cartridge with a 400 grain bullet and I’m glad to see that you are attending that. If you could please give us the details on the case head issue with the brass you were using and how many reloads you used? we’re you getting any other pressure signs? Thank you.

quote:

Originally posted by Jgrabow6493:
I like it. I used a Weatherby Southgate Mauser for the build. I got it for a good price because the rifle had a repaired and refinished stock that I later sold. I used a NOS Browning FN Mauser stock I bought from Western Gun Parts Ltd., Canada to restock the rifle. Re-barreled with a 423-14 CM 6-groove #5 contour Lilja barrel. No issues with feeding so far. Scoped rifle weighs 9 lb 6 oz unloaded and no sling. I use H4895 and Varget and get 2260 to 2300 fps @ 15' from the muzzle. The last reloads are showing case head separation???? Recoil is what you would expect from a rifle of the weight and caliber. I purchased a separate "neck and throating reamer with a removable pilot for D'Arcy Echols' version of the 404-375 H&H" and a "standard 375 H&H reamer" from Hugh Henriksen, Henriksen Tool Co Inc. My gunsmith asked why I didn't have just one reamer made. That would be the only change I would make. The picture shows a 404-375 H&H round next to a 375 H&H round.

Ain’t it Gorgeous?!?!?
The beauty is it’s simplicity and ease (Cost)of conversion.

quote:

Originally posted by Capt Oscar:
Love the look of this round. How many reloads are you getting before signs of case head separation? Would you be willing to rent out the reamer (pair)??

I did the 2.8” case length. The brass is someones basic brass, no markings and I don't remember who made them. I didn't keep track of the number of loadings per case. I went back and checked my notes and I reloaded for this caliber 9 different times but I didn't load all the cases at any one time so some of the cases could have been loaded 9 times. I worked up loads using H4895 and then switched to Varget. I don't see any other pressure sign. I purchased Norma basic brass recently and will try these but I will keep track of the number of loadings this time.

Capt Oscar, I would like to sell both reamers if you are interested.

Thanks for sharing
If you have some preference on loads, please share that as well so more people can benefit from your knowledge.

boomstick,
you shall go down in the annuals of history turning the 404 into a belted magnum and the belt haters are organized and hateful, beware!!

Sounds like a neat wildcat btw I am not of the belt hater clan, I think they are stupid!

I’ll take the slings and arrows for greatness

quote:

Originally posted by Atkinson:
boomstick,
you shall go down in the annuals of history turning the 404 into a belted magnum and the belt haters are organized and hateful, beware!!

Sounds like a neat wildcat btw I am not of the belt hater clan, I think they are stupid!