Quickload Request

[1972RedNeck]

Can anyone run a Quickload for me? Pressure and velocity.

375 Weatherby - 90 Grains of IMR 4350 under a Speer 2472 270 grain bullet seated to 3.605" over all length.

Rifle seems to like it, shoulder seems to hate it.

[44 AMP]

I don't run that, sorry, but I suspect the answer would depend at least in part on what brass you are using. Factory made brass could (and probably is) a bit different than brass formed from another case.

SO, I'd think that the case (and the primer) would be information important to include.

[stagpanther]

CAUTION: The following post (or a page linked to) includes or discusses loading data not covered by currently published sources of tested data for this cartridge (QuickLOAD or Gordon's Reloading Tool data is not professionally tested). USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assumes any liability for any damage or injury resulting from the use of this information.


I took a look at it--even with your extended COL it looks to be a compressed load of almost 108% and QL returns 71,129 psi vs Pmax of 63,817. Weatherbys are known for running up and taking higher pressures; but my understanding some of that is based on the freebore design which is deliberately elongated mitigating the peak pressure "hit." QL says DO NOT USE THIS LOAD in case you're wondering.

[ligonierbill]

Hornady 11 lists 84.8 as max. I don't always color inside the lines, but not that far out. What does your load chrono?

[mehavey]

...90 Grains of IMR 4350 under a Speer 2472 270 grain bullet seated to 3.605"

71,129 psi vs Pmax of 63,817

That's primer-pocket abuse country as an indicator after a few reloadings.
No bright spot/ejector swipe on the case head?


STAG (and others): Go look at Lyman's 50/51st load listings for the 375Wthby and the Barnes 270 TSX/using(Accurate) 4350
Compare against Quickload for same data.
Something very strange going on here.

[stagpanther]

STAG (and others): Go look at Lyman's 50/51st load listings for the 375Wthby and the Barnes 270 TSX/using(Accurate) 4350
Compare against Quickload for same data.
Something very strange going on here.

You mean why are the max loads over 100 grains? My 50 edition of Lyman lists the 378 WM--not the 375. They are different. Why Lyman chose to list it instead of the more widely accepted 375? I have no idea, other than possibly it features one of their low power cast bullets loads. I think the principal difference is the 375 is descended from 375 H&H whereas the 378 (and 416 and 460) are descended from 416 Rigby.

Which puts me in error of an earlier comment on another thread I made on the 375 WbM saying it was related necked version of the 416--it is not.

I plugged in the AA 4350 data I think you are referring to and QL returns just over 95% fill for the max load of 105 grs. it's somewhat over the max psi--but not by much. In my Lyman manual they are careful to say only to be used in Mark V's--weatherby's biggest magnums in the Mark V come with their famously over-built 9 radial lug bolt so that wouldn't concern me very much. Again--this is for what is listed as 378 Weatherby in my manual.

[ligonierbill]

A number of my manuals include the 378 but have dropped the 375. Hornady includes it, with a nice brief writeup. Apparently Weatherby dropped the 375 when they brought out their monster, but brought it back "by popular demand". The 375 Weatherby is more like an improved 375 H&H, shading the old guy by about 150 fps, or there abouts. According to Hornady, you can fire 375 H&H rounds from a Weatherby rifle. That would be a big draw to a lot of folks.

I have never fired one, nor any of the 378 family.

[stagpanther]

A number of my manuals include the 378 but have dropped the 375. Hornady includes it, with a nice brief writeup. Apparently Weatherby dropped the 375 when they brought out their monster, but brought it back "by popular demand". The 375 Weatherby is more like an improved 375 H&H, shading the old guy by about 150 fps, or there abouts. According to Hornady, you can fire 375 H&H rounds from a Weatherby rifle. That would be a big draw to a lot of folks.

Totally agree with that--plus a number of big 5 game safari countries started requiring a minimum 416 caliber, so then the 378 sorta became redundant with the ready availability of weatherby's 416, and 460 based on the rigby.

I have never fired one, nor any of the 378 family.

I don't think you can even buy any of Weatherby's "monster" magnums anymore without the in-line accubrake and pachy decelerator pad. They make shooting their most powerful cartridges very reasonable IMO.

[1972RedNeck]

That's primer-pocket abuse country as an indicator after a few reloadings.
No bright spot/ejector swipe on the case head?

No pressure signs at all. Easy extraction. Deprimed a couple cases (still had very rounded corners on Winchester LRMs) and the new primers were nice and snug going back in.

But coming from a 9# rifle, my shoulder took some abuse...

[44 AMP]

Hornady #7 lists 84.8gr IMR 4350 as max under a 270gr bullet, 2700fps fired from a 24" Weatherby Mark V rifle. Cases were reformed Frontier .375 H&H.
Winchester LRM primers. COAL not given.

[stagpanther]

But coming from a 9# rifle, my shoulder took some abuse...

what is said rifle--and does it have any kind of brake and pad? 9 lbs should be plenty of weight. If you can get any kind of chrono figure might be able to "reverse engineer" approximate psi. 90 grs still sounds like "pushing your luck" if it's more of conventional 2 or 3 lugged bolt.

[stagpanther]

Hornady #7 lists 84.8gr IMR 4350 as max under a 270gr bullet, 2700fps fired from a 24" Weatherby Mark V rifle. Cases were reformed Frontier .375 H&H.

What's interesting about this is that I scrolled down to their 300 gr loads and noticed they have a max loads for their 300 gr DGX beyond those for the 270 bullets--not far off from 90 grs. I plugged their max load numbers into QL for the various "flavors" of 4350 for the 300 gr bullet--IMR returned 73,841 psi for 87.7 grs, H4350 returned 71,694 for 87.1 and Accurate returned 71,288 psi for 86.1. Maybe it has to do with the burn characteristics and start pressure for 300 gr projectiles?

[1972RedNeck]

What's interesting about this is that I scrolled down to their 300 gr loads and noticed they have a max loads for their 300 gr DGX beyond those for the 270 bullets--not far off from 90 grs. I plugged their max load numbers into QL for the various "flavors" of 4350 for the 300 gr bullet--IMR returned 73,841 psi for 87.7 grs, H4350 returned 71,694 for 87.1 and Accurate returned 71,288 psi for 86.1. Maybe it has to do with the burn characteristics and start pressure for 300 gr projectiles?

Hornady's data for the 300s is nearly identical to Ackley's with IMR4350.

In general it seems like lighter bullets can be loaded with more powder to get the same pressure, all else being equal (which it never is). Hence why I was alright creeping up to 90 grains with 270 grain bullets.

The other thing I may have going for me is that I seem to have a slightly longer chamber than saami spec. At least my Redding die instructions say to bottom the sizing die out on the shell holder which is supposed to result in cases being formed to saami spec. I just bumped the shoulder back .002” which left the die about .040” above the shell holder. Not a lot of difference, but a little more case capacity than standard.

[1972RedNeck]

what is said rifle--and does it have any kind of brake and pad? 9 lbs should be plenty of weight. If you can get any kind of chrono figure might be able to "reverse engineer" approximate psi. 90 grs still sounds like "pushing your luck" if it's more of conventional 2 or 3 lugged bolt.

FN Mauser 98. No brake. Just bought a decelerator pad for it. Not terrible until I start working up loads for it. 40 to 50 rounds in a day is more than enough.

[stagpanther]

Ah--looks like you moved fast and bought that rifle from molly dude--congrats if that's the case. 40 to 50 shots a day? That's a lot of big bang to get hammered with repeatedly. I can do about a dozen with the 416 wby mag but don't go beyond that since my ability to maintain good accuracy will fall away after that--just the concussive report alone starts to jangle my skull and what little is in it. LOL

The other thing I may have going for me is that I seem to have a slightly longer chamber than saami spec

I had a suspicion that might be the case considering how much longer you seated your bullet.

In general it seems like lighter bullets can be loaded with more powder to get the same pressure, all else being equal (which it never is). Hence why I was alright creeping up to 90 grains with 270 grain bullets.

But in this case hornady lists more powder for the 300 gr bullet than the 270 gr one. That's what I find unusual.

[44 AMP]

But in this case hornady lists more powder for the 300 gr bullet than the 270 gr one. That's what I find unusual.

Unusual, ok, but not unheard of. Remember that the gun they used for testing is not your gun, or my gun and each of them could be at different places on the bell curve.

Most guns will fall somewhere near the middle of the curve, which is why reloading data is a useful guideline. But its also possible your gun will be at the high end of the curve, theirs in the middle and mine at the low end, or any combination of possibilities.

Guidelines, not Holy Writ.

[stagpanther]

Unusual, ok, but not unheard of. Remember that the gun they used for testing is not your gun, or my gun and each of them could be at different places on the bell curve.

Most guns will fall somewhere near the middle of the curve, which is why reloading data is a useful guideline. But its also possible your gun will be at the high end of the curve, theirs in the middle and mine at the low end, or any combination of possibilities.

Guidelines, not Holy Writ.

Agreed--but when I see a difference as marked as that--I'm kinda curious to know why. These powders might have a different cut between them or slightly different burn rates--perhaps inside a cavernous case with a heavier bullet to propel changes the ignition characteristics. "Funky" ignitions can introduce secondary pressure spikes a shooter may never know are happening; something I always think about when firing big hand loads, especially when I can hear a noticeable delay in firing or see a noticeably differnt exhaust coming out of the muzzle between cartridges of the same loads.

[Unclenick]

CAUTION: The following post (or a page linked to) includes or discusses loading data not covered by currently published sources of tested data for this cartridge (QuickLOAD or Gordon's Reloading Tool data is not professionally tested). USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assumes any liability for any damage or injury resulting from the use of this information.


A longer bullet ogive can do it, too, by allowing more starting gas to bypass the bullet and head down the barrel before the bullet obturates the bore. That reduces pressure. I note from photos of Hornady's test setup that they have what looks like pressure-measuring instrumentation on the barrels. However, I believe they still load to velocity intervals and then use the last interval load before one when over SAAMI pressure. Some of those will be close, and some will be nearly a full interval lower, so the peak pressures aren't necessarily very close to SAAMI max. IIRC, when I looked at that some years back, it appeared their top loads in a few cartridges I looked at (not exhaustive) varied from about 1% to 9% below SAAMI max. I would expect Sierra and anyone else posting charge weights in velocity intervals would have the same thing occur in their data.

I vaguely recall hearing there was some point in the Weatherby's history when the long freebore was changed, but I don't recall which way or when. Perhaps someone with more knowledge than I have about Weatherbys can chime in and sort that out. I mention it simply because it could be a factor in pressure discrepancies.

CIP shows the 375 Weatherby freebore as about 0.36 inches. Using that much bullet jump in GRT (which has this feature while QL does not) drops the pressure of the 90-grain load from roughly 74,000 psi to 66,000 psi. Add to that a slightly large chamber, and the OP's loads could score the 63,800 psi (4400 bar) limit the CIP has for its average peak pressure. So, it's possible this is still good to go, though pushing powder charge and pressures will always erode throats and hasten the end of barrel life. There is no free lunch. You also still have to consider the OP's individual lot number of IMR4350 could be a little slower than average, too. Lots of variables.

It's too bad Jim Ristow had to shut down his Pressure Trace business (health reasons, not lack of product interest), as that was the best way for a handloader to check the pressure in an individual gun.

[1972RedNeck]

Ah--looks like you moved fast and bought that rifle from molly dude--congrats if that's the case. 40 to 50 shots a day? That's a lot of big bang to get hammered with repeatedly.

Nah, I picked this one up on GB awhile back. Finally got some nice weather to really work with it.

I am lucky that I can set some targets up right out my back door out to 300 yards with a nice steep bank for backup. Makes it really convient to work up loads, but sometimes I get carried away and keep tweaking and shooting.

[1972RedNeck]

CIP shows the 375 Weatherby freebore as about 0.36 inches. Using that much bullet jump in GRT (which has this feature while QL does not) drops the pressure of the 90-grain load from roughly 74,000 psi to 66,000 psi. Add to that a slightly large chamber, and the OP's loads could score the 63,800 psi (4400 bar) limit the CIP has for its average peak pressure. So, it's possible this is still good to go, though pushing powder charge and pressures will always erode throats and hasten the end of barrel life.

Thank you

What kind of velocities does it show for a 24" barrel with each of those pressure scenarios?

[Unclenick]

CAUTION: The following post (or a page linked to) includes or discusses loading data not covered by currently published sources of tested data for this cartridge (QuickLOAD or Gordon's Reloading Tool data is not professionally tested). USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assumes any liability for any damage or injury resulting from the use of this information.

GRT produces 2949.7 fps and 2868.5 fps for the short and full freebore, respectively. Perhaps you can get a clue out of that, but keep in mind this assumes a Velocity and Pressure barrel configuration with a bore that is nominally dimensioned and cold. If you shoot for velocity as a pressure check, let the barrel cool for a few minutes between shots. Keep in mind the computer simulators don't take all sources of heat loss into account, so you can only trust its numbers up to a point.

[stagpanther]

It's too bad Jim Ristow had to shut down his Pressure Trace business (health reasons, not lack of product interest), as that was the best way for a handloader to check the pressure in an individual gun.

I didn't know that--I still have mine. Is there anyone who is picking up the slack for support?

A longer bullet ogive can do it, too, by allowing more starting gas to bypass the bullet and head down the barrel before the bullet obturates the bore.

I thought about that--but it seems to me dangerous game solids would do almost the opposite (?).

[TX Nimrod]

… I note from photos of Hornady's test setup that they have what looks like pressure-measuring instrumentation on the barrels. However, I believe they still load to velocity intervals and then use the last interval load before one when over SAAMI pressure...

That’s not how they used to develop their data. Older manuals showed a graphical solution: they plotted curves which fit the velocities of different powder charges against those charge weights. Where the curve intersected the graph’s 100 fps intervals was the charge weight published for each 100 fps interval. Any load which showed excess pressure was backed down to the next lower velocity interval.

To try to load for exact specific velocities would make no sense. I’m sure that today they use best-fit software to do the same thing - it isn’t 1967 anymore.


.

[Unclenick]

They may still develop it that way initially. I know they test their maximum loads in SAAMI V&P barrels. I think everyone does that now to avoid liability issues, but it's just to make sure they don't go over. Rigging strain gauges to their standard test setup is a good way to preview what they can expect from that final test. I'm mainly just pointing out that by dropping to the next lower interval below SAAMI max like that, you will get some instances of that drop being a fraction of an interval and some for which it is almost a full interval. In the latter case, peak pressure can be noticeably below SAAMI max. Also note that they cluster same-weight bullets together so that the same liability concern would likely tend to make them validate the bullet that makes the highest pressure in the bunch, and the others are going to be off a little.

Originally Posted by stagpanther

I didn't know that--I still have mine. Is there anyone who is picking up the slack for support?

Jim was looking for an alternative source for the strain gauges, but I don't think he found one. He'd said he'd be shuttering the business at the end of the year, but it was gone already in mid-December, so I hope his health issues didn't force early closure. You can buy strain gauges on Amazon that would likely work fine, despite the shape difference, but you have to deal with the connector. When I was in Tokyo last month, I picked up fifty sets of 2 mm connectors in a small shop near the Akihabara station, where all the small electronic component shops were clustered when I was there in the 1970s. Not much of that is left now, though. The era of disposable pre-assembled electronics has hit those small shop owners hard. Anyway, these connectors looked about right and, even if they don't match exactly, can be wired in to substitute. So, I figure to be improvising this way in the future.

Originally Posted by stagpanther

I thought about that--but it seems to me dangerous game solids would do almost the opposite (?).

It really depends on the design details. I don't think there is a universal answer to this, but for the specific Speer BT SP bullet the OP specified, it seemed to work out.