Big bore load development process

[Wyatt Smith]

Speer load data for 350 grain bullet. It doesn’t show 748

 

[Wyatt Smith]

Sorry that’s already been posted.

 

[CoElkHunter]

Speer load data for 350 grain bullet. It doesn’t show 748
View attachment 321074

Yeah, nobody has much load data for using W748 for many of the larger bore rifles. Hornady has data for the 500gr (not TSX bullets) .458 using 748 and very surprisingly, I was looking at Barnes loading data today, and they have loads in .375 h and h using 748 with their 270 and 300gr TSX bullets! I used 748 for years in loading .308W and .22-250. It’s not the best powder for many cartridges, but I have nine pounds of it and want to use it up?

 

[CoElkHunter]

Can't imagine any problem if you stay within the load parameters. Speer shows a COAL of 3.105" in their data for their 350 gr bullet in the 458 WM.

The nose length- from the front of the last groove to the nose for the 450 Barnes TSX is .86" so adding that to a trim length of the WM of 2.490" = a COAL of 3.35" which us just .01" over the listed max for the WM of 3.34". Unless something is too "tight" in your rifle that is plenty close enough so it should work fine for length. Most 458 WMs have a long throat and .01" shouldn't matter at all for magazine clearance or feeding.

View attachment 321071

I guess your right. Hornady shows their 350gr Interlock with a coal of 2.950? That’s a lot of space between the bullet in the chamber and the rifle lands? New to me? Guess it’s all good? Freebore anyone?

 

[fourfive8]

Extra freebore can be a good thing especially in a DG rifle. May provide some insurance against an unexpected high pressure event. And you might check the actual freebore to land contact. Some or most? WMs have a fairly long throat/ freebore anyway, designed to accommodate 500-510 gr bullets seated well out allowing for max powder capacity.

 

[CoElkHunter]

Extra freebore can be a good thing especially in a DG rifle. May provide some insurance against an unexpected high pressure event. And you might check the actual freebore to land contact. Some or most? WMs have a fairly long throat/ freebore anyway, designed to accommodate 500-510 gr bullets seated well out allowing for max powder capacity.

Well the rifle I’m using is a newer CZ 550, so it probably has the longer throat? What’s kinda of strange is the factory Barnes cases I have shot through it apparently don’t need to be resized yet, as their lengths are the same as my unfired brass and they chamber fine without a bullet in them? I always have to at LEAST neck size or some shoulder sizing with bottleneck cases AND trim the cases to correct length?

 

[fourfive8]

All sounds good so far. An important number for different bullets is the " jam" length. That means the total COAL where the ogive of the bullet first contacts the lands. All bullets are different- some very different. Two or three ways to determine it. An easy way is to resize a case and don't prime or charge it. Barely seat the test bullet into the neck - 1/8" to 1/4" or so. Slowly and gently chamber the round and gently feel for contact of the bullet's ogive with the lands in the bore. If you feel contact before full bolt closure and turn then remove test cartridge and nudge the bullet down a very small increment with the seating die and try again. Repeat this until you feel no contact between bullet ogive and lands.... that is the "jam" length for that bullet. Record that COAL in your load log.

 

[fourfive8]

When doing the "feel at contact" test, also a good idea to "smoke" the bullet to confirm contact with lands. Sometimes I use a felt tip to mark bullets but candle soot is better I think because it shows more easily with the lightest scuff at lands contact.

Here's a soot smoked bullet before and after checking. The land contacts marks can be very small, less obvious and smaller than this, especially if using a felt tip or similar marker. And the shorter the land mark, the closer the seating depth is to the true jam length.

 

[Hyde Hunter]

I am just starting to do some work with this on a new CZ using 400 and 450 gr Barnes bullets.the 450's will be seated out to 3.60 or a might longer to allow more powder and velocity. the magazine is long enough and velocity will be a little less than the Lott I used to have one. interesting reading and tons of info by a lot of Lott and Win Mag shooters.I just wish it would get warmer here than zero degrees to start load work

 

[Fred Gunner]

My question would be what ammo will you be hunting with Factory or your own loads?

I hunt with factory Swift ammo. So I reload to exact factory specs for training ammo.

 

[Hyde Hunter]

I have not shot anything but my hand loads for over 45 years the only factory ammo is for a 22 long rifle

 

[CoElkHunter]

All sounds good so far. An important number for different bullets is the " jam" length. That means the total COAL where the ogive of the bullet first contacts the lands. All bullets are different- some very different. Two or three ways to determine it. An easy way is to resize a case and don't prime or charge it. Barely seat the test bullet into the neck - 1/8" to 1/4" or so. Slowly and gently chamber the round and gently feel for contact of the bullet's ogive with the lands in the bore. If you feel contact before full bolt closure and turn then remove test cartridge and nudge the bullet down a very small increment with the seating die and try again. Repeat this until you feel no contact between bullet ogive and lands.... that is the "jam" length for that bullet. Record that COAL in your load log.

The COAL is really confusing me (I confuse easily! Ha!). Last night I loaded some Barnes 450gr. TSX .458WM and put a mild roll crimp in the upper bullet groove (not really a cannelure?). Same length as the factory Barnes 450 TSX I have. The coal looks to be about 2.98” according to my “state of the art” 1970 something Ohaus manual scale. Then I loaded some 350gr Speer Mag Tips and put a mild roll crimp to almost the top of the cannelure. Coal is about 2.74”. Both of these coals look to be well below the published data for each bullet respectively? Is the COAL the MAXIMUM length or IDEAL length for a given bullet loading? Thanks!

 

[CoElkHunter]

Speer load data for 350 grain bullet. It doesn’t show 748
View attachment 322473

My 2016 Hornady manual shows 80.8 grains of H335 as maximum with a 350gr bullet? Yours shows 85 grains? Strange? I just loaded 77 grains last night, thinking it was a medium load? Now I’m wondering which reloading manual or data to believe?

 

[Forrest Halley]

The COAL is really confusing me (I confuse easily! Ha!). Last night I loaded some Barnes 450gr. TSX .458WM and put a mild roll crimp in the upper bullet groove (not really a cannelure?). Same length as the factory Barnes 450 TSX I have. The coal looks to be about 2.98” according to my “state of the art” 1970 something Ohaus manual scale. Then I loaded some 350gr Speer Mag Tips and put a mild roll crimp to almost the top of the cannelure. Coal is about 2.74”. Both of these coals look to be well below the published data for each bullet respectively? Is the COAL the MAXIMUM length or IDEAL length for a given bullet loading? Thanks!

COAL... Cartridge Over All Length... Is a term that gets abused.
It is not the SAAMI maximum length nor is it the maximum loadable length for your rifle necessarily. It gets taken by these various manuals and contorted into the ideal length for their given bullet. Caution with the Barnes in that it is rumored that the mono bullets are longer than cup and core bullets and something has to give...powder capacity or OAL...

 

[CoElkHunter]

COAL... Cartridge Over All Length... Is a term that gets abused.
It is not the SAAMI maximum length nor is it the maximum loadable length for your rifle necessarily. It gets taken by these various manuals and contorted into the ideal length for their given bullet. Caution with the Barnes in that it is rumored that the mono bullets are longer than cup and core bullets and something has to give...powder capacity or OAL...

Oh yeah, the Barnes are a LONG a** bullet for their weight. Never loaded them before, but they load into the case well. As far as the COAL with the .458WM, I guess you can load them to 3.340”! That’s a LOT of room for powder and shoulder abuse! I’m not going to do that, but I’m more concerned about the minimum COAL, like with the 350gr bullets? I guess when I fire them, they’ll make it out of the chamber and into the barrel eventually? Ha! Ha!

 

[Hyde Hunter]

I just loaded one round to check velocity starting with 74.0 gr of 2230 powder and seated the bullet to 3.600 using the Barnes 450 gr TSX crimped 3rd grove down no powder compression chambers fine in fact loaded 4 dummies to check feeding and all is well.if it was not below zero right now I would go to the gun room/reloading room and give you the max length that I measured for my CZ550 it is a 2008 production but is brand new unfired other than the 3 shot factory target. you will also get higher velocity if you use 2230 powder

 

[Forrest Halley]

Oh yeah, the Barnes are a LONG a** bullet for their weight. Never loaded them before, but they load into the case well. As far as the COAL with the .458WM, I guess you can load them to 3.340”! That’s a LOT of room for powder and shoulder abuse! I’m not going to do that, but I’m more concerned about the minimum COAL, like with the 350gr bullets? I guess when I fire them, they’ll make it out of the chamber and into the barrel eventually? Ha! Ha!

You're not the first person to shoot a 350 out of a .458. surely other ingenious folks have seen the utter versatility of the .458 bore with all those little .45-70 bullets. I was lucky enough to shoot a .45-70 and then I realized that the .458 was better and then I realized that a Lott was even better. At some point I might just drive one of those tiny bullets at murderous velocity for giggles. I'm having fun with 500's right now.

 

[CoElkHunter]

I just loaded one round to check velocity starting with 74.0 gr of 2230 powder and seated the bullet to 3.600 using the Barnes 450 gr TSX crimped 3rd grove down no powder compression chambers fine in fact loaded 4 dummies to check feeding and all is well.if it was not below zero right now I would go to the gun room/reloading room and give you the max length that I measured for my CZ550 it is a 2008 production but is brand new unfired other than the 3 shot factory target. you will also get higher velocity if you use 2230 powder

Wow, 3.600! Interesting! I have some 500gr Barnes TSX I’ll have to load out a bit as I need to use up Winchester 748 powder and I know it will have to be compressed unless I load the bullet out a bit. I too have a newer CZ 550 that I’m loading these .458s for. I love my rifle!

 

[CoElkHunter]

You're not the first person to shoot a 350 out of a .458. surely other ingenious folks have seen the utter versatility of the .458 bore with all those little .45-70 bullets. I was lucky enough to shoot a .45-70 and then I realized that the .458 was better and then I realized that a Lott was even better. At some point I might just drive one of those tiny bullets at murderous velocity for giggles. I'm having fun with 500's right now.

Yeah my .458WM is my first .45 caliber rifle. I have really enjoyed shooting it and now starting to reload it. It’s taken me awhile to gather (buy) all of the bullet components and die set, etc., but I’m able to reload it now with my 1970s era reloading equipment. I have TWO RCBS balance beam powder scales to double check powder charges, but have ordered an inexpensive electronic digital powder scale. The older equipment I have is slower, but I’m not in a hurry and rather be more precise when loading.

 

[Forrest Halley]

Yeah my .458WM is my first .45 caliber rifle. I have really enjoyed shooting it and now starting to reload it. It’s taken me awhile to gather (buy) all of the bullet components and die set, etc., but I’m able to reload it now with my 1970s era reloading equipment. I have TWO RCBS balance beam powder scales to double check powder charges, but have ordered an inexpensive electronic digital powder scale. The older equipment I have is slower, but I’m not in a hurry and rather be more precise when loading.

CANCEL THE ORDER. Electronic scales are worthless and require batteries. I trust the balance and I've been burned by the digital. If I were going to spend money on a digital scale it would be hooked to an electronic powder trickler. If it isn't, I don't see the point.