grtools.de Internal Ballistics software (free)

[Oldbloke]

Hi,
First let me state I'm no reloading expert.
There has been mentioned here in the past a mention of grtools. Also quick load. GRTools is free.

These are software to predict/calculate cartridge pressures, velocities, energy etc of loads when fired. Please note these are not precise, they are a guide only. So treat them as such.

So, being retired I decided to have a look at grtools.de as it is free.

You need to register to download the software, a simple process. The down load is abt 225mb and will need to be unzipped. You can run it on your PC but I opted to unzip it to a usb memory stick and so far so good. If you wish you can also register to the discussion board using discord.

I've only used this so far to ascertain the approximate velocity of a few of my hand loads and I would have to say its easy to get a hang of. If I can anyone can.

So far, so good. I think re-loaders should consider having a crack at this software. It just gives you more info in addition to powder manufacturers data.
There are plenty of powders included and ADI is there. Would just be nice if there was a bit more. Plenty of projectile choices too.
Here is a screen shot. Velocity and energy figures are clearly shown in the "results" tab.
The left tab is where you make various selections for powder, proj etc,

223 Super Roo 55gr 24gr.JPG (173.55 KiB) Viewed 1347 times

http://www.grtools.de

https://www.thereloadersnetwork.com/201 ... art-using/

https://m.youtube.com/watch?v=sehV1jeHa ... _rel_pause

The file size is about 225mb

Just a note. The writer and main manager of this software has unfortunately passed away recently. The project relies on members contributing additional real data to improve the accuracy of the predictions. So additional data contributions have been halted for the time being but it seems the intention is to continue the project.

[on_one_wheel]

Looks pretty awesome for free software

Hopefully, with the writer /manager Unfortunately passed away, someone is going to keep it going.. I'm sure there'll be work to do on thd background and costs related to Web hosting

[Oldbloke]

Looks pretty awesome for free software

Hopefully, with the writer /manager Unfortunately passed away, someone is going to keep it going.. I'm sure there'll be work to do on thd background and costs related to Web hosting

Yep, there seems to be an additional 6 or 7 people involved. I guess someone will put their hand up.

[Blr243]

I’m interested in gr tools but can never successfully load it. I’m wanting to know if I can use red dot in my bushmaster with a 405 gr cast lead Bullet 1200 FPS

[bladeracer]

I’m interested in gr tools but can never successfully load it. I’m wanting to know if I can use red dot in my bushmaster with a 405 gr cast lead Bullet 1200 FPS

I've downloaded it a few times, had a quick play each time and given up on it very quickly.

They use Red Dot in .45-70 and .444 don't they?
Those are much larger cases than the BM (79gn and 69gn compared to 59gn H2O for the BM) so I can't see it being a problem.
But the 405gn bullets might be a bit much for it, I think people generally use Red Dot under bullets closer to 200gn.
Do you want to use it because it because you have nothing more suitable for it?

[Blr243]

Blade I can’t get enough trail boss in the little case Have a stack of red dot not sure if adi I make any suitable powders. It’s not an immediate problem.. my bushmaster has become a safe queen ever since I bought my 4570. This 4570 so much easier to load for from gentle all the way to brutal

[Blr243]

Hoping old bloke gets bored one day and runs my situation on his computer

[bladeracer]

Blade I can’t get enough trail boss in the little case Have a stack of red dot not sure if adi I make any suitable powders. It’s not an immediate problem.. my bushmaster has become a safe queen ever since I bought my 4570. This 4570 so much easier to load for from gentle all the way to brutal

Maybe somebody can run your situation through this software and see what ideas it comes up with.

Do you mean you can't make the 1200fps you want using Trailboss? I doubt any of the fast pistol powders are likely to make much more, Red Dot (like Trailboss) would be used for reduced loads, even subsonic. In the short Bushmaster I would think even 1200fps is a pretty stout load for a 400gn bullet, not what I would consider a reduced load. If you want higher velocity with the heavy bullet I would think you'll want a slower rifle powder, or use a lighter bullet. If you don't have AR2205 or AR2207 I'd be experimenting with AR2206H.

You can probably get a 400gn bullet to about the 2000fps mark in a 16" (I'm assuming your BM is 16") .45-70 I would think, but that's got 33% more case volume, and would be pretty hot. At the other end of the scale the .44 Mag only has 39gn H2O and .45 Colt is 42gn. I have seen data for 400gn bullets in the .45 Colt, but loaded way over standard length to increase case volume significantly (thus reducing the pressure) - you could try this if you don't mind single-feeding them. I don't know what powder they were using or what velocities they were seeing, I think it was a failed experiment for dropping silhouettes from memory. I doubt they were getting close to 1200fps though, and I doubt it was in a revolver or lever-action. I don't know that I'd consider 400gn bullets very effective in the BM, but I guess with pure lead at extremely close ranges they'd be similar to 12ga slugs.

[bladeracer]

Hoping old bloke gets bored one day and runs my situation on his computer

Really, it's a useful example for anybody trying to get their head around the software, also be interesting to see if ten different people did it whether we'd get ten different answers