Question for the experienced handloader

[BlackRhino]

I am going to handload the .375 H&H& Magnum to the max (buff loads) using 350 grains Degol bullets (RN and FMJ). In Europe American powders are sometimes hard to come by. Hence, I will use either Swedish Bofors or Finnish Vit powders. I could not find published data for 350 grains and therefore I would like to use simulated loads to start with. Are there any significant differences in simulated data between Quickload and the Freeware Gordan's Reloading Tool (GRT)? Your help is highly welcome!!!

 

[Nhoro]

I use GRT but Have compared it to Quickload and to normal reloading manuals. I find GRT and Quickload pretty similar. I think both are pretty conservative with regards predicted pressure and velocity. I have had one load workup that went past their dangerous pressure before showing pressure signs. These are just my observations, work up your loads slowly looking for pressure signs!

I would also avoid pushing for velocity in big bores. You don't need max velocity for big game and it can lead to extraction problems. I have a friend who I have reloaded with and we loaded a hot load and fired it on the highveld where I live- cool and higher altitude. He said that same load has had extraction problems in the Zambezi Valley. My preferred load for my 458 lott is Vihtavuori N 133 and 515 gr Pergrines at 2195 fps. Not a max load, but absolutely capable. No pressure signs and reliable at any temperature.

 

[uplander01]

I’d pull up a burn rate chart and cross reference the Woodleigh load data for .375-350’s with the listed powders to similar burn rate powders for the brands you have access to. There is no reason, really ever, IMO to push a dangerous game rifle to absolute max powder charge and velocity….asking for trouble in extreme heat, which you will encounter if you hunt Africa enough.

 

[7x57Joe]

Rather than trying to wring out all the velocity, I'd recommend a larger bore. An extra 50-75 fps may cause more harm than good.

 

[Rare Breed]

I use GRT but Have compared it to Quickload and to normal reloading manuals. I find GRT and Quickload pretty similar. I think both are pretty conservative with regards predicted pressure and velocity. I have had one load workup that went past their dangerous pressure before showing pressure signs. These are just my observations, work up your loads slowly looking for pressure signs!

I would also avoid pushing for velocity in big bores. You don't need max velocity for big game and it can lead to extraction problems. I have a friend who I have reloaded with and we loaded a hot load and fired it on the highveld where I live- cool and higher altitude. He said that same load has had extraction problems in the Zambezi Valley. My preferred load for my 458 lott is Vihtavuori N 133 and 515 gr Pergrines at 2195 fps. Not a max load, but absolutely capable. No pressure signs and reliable at any temperature.

Completely agree!!! Loading to the max rarely yields good groupings and are never needed

 

[BlackRhino]

Maybe I have not been very precise. The main question was whether there are differences between the two simulation programmes.

Special thanks to Nhoro for his helpful answer.

It is not my aim to drive the .375 to its absolute max but to find reliable heavy loadings with Bofors and Vitavuori. While Bofors is similar or even identical to Norma or Rottweil relative burning rate that are available do not include my powders that I have at hand. Moreover, using relative burning rates can give only a very rough idea of the powder load.

If you handload 350 grainer bullets (Degol or Woodleigh) in .375 I would be very happy if you can share your data.

While in certain handbooks for softs and FMJ identical powder charges are given, the blue Rottweil book lists slightly differences. Do you use identical loads for softs and classical FMJs of same weight?

Thanks in advance!

 

[Kevin375]

Hi Black Rhino.

I had the opportunity to reload these Degol 350 gr bullets (Lion Load and Starkmantel ) for my Blaser R93 in .375 Holland & Holland magnum at the beginning of the year.
Being European, I used Reload Swiss powders that are well spread in Europe now.
I played with the RS60 and the RS70 and both work. I kept the RS60 for hunting because the accuracy was better in my rifle and there is no compression.
Quickload doesn't give a good result with velocity if my memory serves.
You can expect 700-710 m/s with a 65 cm barrel.

 

[BlackRhino]

@Kevin375
Thanks for charing your experiences in .375 with heavy Degol bullets. Are you a BGS fan?

I downloaded GRT, fooled around with the programme and noticed that GRT simulations deviate significantly from Handloader Manual Data (for instance blue Rottweil book) at least in 375 H&H.

@all
The question is, whether simulated GRT loads can generally be used if a 15% safety margin (pressure) is applied?

I found that RS60 looks like a very effective powder in .375 with heavy bullets. Using Winchester brass (H2O volume measured) would result in 740 m/s with 350 Degol RN applying a 15 % safety margin with 65 cm barrel. That's looks very promissing.

@Kevin375
Did you use a load with > 15 % safety margin for you loads?

@all
What should I use as input powder temperature for African loads?

 

[Nhoro]

@Kevin375
Thanks for charing your experiences in .375 with heavy Degol bullets. Are you a BGS fan?

I downloaded GRT, fooled around with the programme and noticed that GRT simulations deviate significantly from Handloader Manual Data (for instance blue Rottweil book) at least in 375 H&H.

@all
The question is, whether simulated GRT loads can generally be used if a 15% safety margin (pressure) is applied?

I found that RS60 looks like a very effective powder in .375 with heavy bullets. Using Winchester brass (H2O volume measured) would result in 740 m/s with 350 Degol RN applying a 15 % safety margin with 65 cm barrel. That's looks very promissing.

@Kevin375
Did you use a load with > 15 % safety margin for you loads?

@all
What should I use as input powder temperature for African loads?

GRT is based off measured user data. I did interact with the creatir a few years back but he sadly passed away. I sent him velocity data for 458 lott. Basically the more common calibresband bullets have more data. So 375 H&h is common but Degol bullets will have less data than say Hornady.

My loads produced higher velocities than GRT and Quickload predicted so I would start with modest safe loads as predicted by either programme and measure velocities and look for pressure signs before working them up. Both programmes give you a low end and a top end for pressures.I used Pergrine bullets and velocities were 10 % faster than predicted and I suspect pressures were lower.

Hottest temperatures in Zimbabwe would be 45 to 48 deg Celsius and a rifle in the sun can easily get over 69 deg. As I said previously, the guy I reload with has experience with a load that was safe in Harare and not safe in the zambezi valley. However, I think that is for loads on the edge of max pressure already and hotter temps push them over.

 

[Kevin375]

@BlackRhino

The RS60 gave me very good velocities with 300 gr bullets in the past, and Quickload was very close of the velocities recorded with my chronograph.
However, theory and practice doesn't really work with the RS60 and 350 gr bullets from Degol. Same thing with the Accubond 260 gr, at least with my rifle.
I used Hornady cases and I had problems with some them (case separation) but the recipe was not the problem.
The case capacity was 96.4 gr of H20 and my barrel length is 63 cm.
The cannelure was quite high on the bullets.
My COAL was 3.564" and I crimped with the LFC.

Quickload announces 750 m/s (2461 f/s) while my little Garmin Xero only recorded ~ 705 m/s ( 2310 f/s) with the Starkmantel.
The bolt of my Blaser was easy to open and there was no sign of overpressure.
I haven't sent the ammunitions to a proof house to be sure about the pression generated, but in theory, there is still a good margin of safety. But this powder is quite temperature sensitive.
I also tried the Vihtavuori N555 but despite a good accuracy, my velocity was pretty slow ~ 650 m/s ( 2132 f/s).

The 350 gr bullets from Degol is a very good bullet but I have found, with my small datas, the Starkmantel tends to shed more weight than the regular 300 gr.

Girafe : 82.8 %

Eland : 77.3 %