24hourcampfire.com
Previous Thread
Next Thread
Print Thread
Hop To
Joined: Dec 2004
Posts: 168
PA_Bob Offline OP
Member
OP Offline
Member
Joined: Dec 2004
Posts: 168
Maybe I'm late to the party, but been reloading now a couple of decades. Interested to hear users experiences with GRT as an aid in load development--good, bad, accurate, etc.? There are so many holes in manufacturers data with respect to new propellants/powders and new projectiles, complicated by the lack of availability of all of the above that I find I need to create loads out of whole cloth, and I'd like to have a baseline in facts or at least a SWAG. Already installed GRT and playing with it.

BP-B2

Joined: Sep 2021
Posts: 57
2
Member
Offline
Member
2
Joined: Sep 2021
Posts: 57
I've just started playing with this as well. Still learning how to use it.

Joined: Dec 2004
Posts: 10,652
Campfire 'Bwana
Offline
Campfire 'Bwana
Joined: Dec 2004
Posts: 10,652
I've used GRT a little and found that it yields results very similar to QUICKLOAD results. I know that for some cartridges QL gives erroneous solutions, but I don't load any of those myself. I think GRT takes user reports to fine tune their algorithms and that may set it apart from QuickLOAD for those cartridges, but I'd not assume that.


Originally Posted by gonehuntin
Give a communist a helicopter ride, he flies for an afternoon. Throw a communist out of a helicopter and he flies for the rest of his life.....



Joined: Jun 2001
Posts: 1,705
P
Campfire Ranger
Online Content
Campfire Ranger
P
Joined: Jun 2001
Posts: 1,705
GRT is dependent on users submitting accurate data. Popular cartridges with lots of data submissions like the 6.5 CM for example, have been spot-on running what-ifs for me.

However, not-so-popular cartridges such as the 9.3x62mm? The predictions are not even close.

Joined: Oct 2009
Posts: 5,390
Campfire Tracker
Offline
Campfire Tracker
Joined: Oct 2009
Posts: 5,390
This doesn't lend much encouragement . . . .
Quote from GRT site

"Important announcement

I just wanted to reach out and let you know that my husband Gordon passed away on January 19th 2022.

Until further notice, this site stays online. Please note that Patreon contributions have been paused.

Initially, no additional submissions should be made to the GRTLab, or Translations, as no one has access to service the data.
Therefore, it will be impossible to update Powder Models, Calibers, and Bullet to the GRT database as an official release until the possibilities of continuing Gordon's fine work are explored.


Take care!
Chrissi "


I never thought I'd grow up to be a grumpy old man, but I did, and I'm killin' it.
IC-A B3

Joined: Jun 2001
Posts: 1,705
P
Campfire Ranger
Online Content
Campfire Ranger
P
Joined: Jun 2001
Posts: 1,705
Oh boy...

Joined: Aug 2011
Posts: 88
Q
Member
Offline
Member
Q
Joined: Aug 2011
Posts: 88
I'm a first time user. I've started with inputting the specs for a 357 herrett since it wasn't in the database. I've not compared results to my barrel, only to the reloading manuals. Results have been within 10%, often closer. I've got some fine tuning to do as several case and chamber dimension inputs were swags or incomplete cartridge diagrams when available. I can't make the bore cross section error message go away. It says input is physically impossible. Not sure what i'm doing wrong here.

Joined: Dec 2004
Posts: 10,652
Campfire 'Bwana
Offline
Campfire 'Bwana
Joined: Dec 2004
Posts: 10,652
A screenshot of what you're seeing might be helpful.


Originally Posted by gonehuntin
Give a communist a helicopter ride, he flies for an afternoon. Throw a communist out of a helicopter and he flies for the rest of his life.....



Joined: Aug 2011
Posts: 88
Q
Member
Offline
Member
Q
Joined: Aug 2011
Posts: 88
This is the message i get

Attached Images
GRTCSError.png (66.58 KB, 103 downloads)
Joined: Aug 2014
Posts: 435
S
Campfire Regular
Offline
Campfire Regular
S
Joined: Aug 2014
Posts: 435
Is Gordon's a free site or a program you purchase?
Soup

IC-B B4

Joined: Aug 2011
Posts: 88
Q
Member
Offline
Member
Q
Joined: Aug 2011
Posts: 88
it's free. just download it and run.

Joined: Dec 2004
Posts: 10,652
Campfire 'Bwana
Offline
Campfire 'Bwana
Joined: Dec 2004
Posts: 10,652
Originally Posted by Quickbeam
This is the message i get


I think the value entered in that field is miscalculated. I am not familiar with the .357 Herrett so I'm not sure whether it's a .357 or a .358, but if you pull up other cartridges in the database you can see what the value should be. For .35 Whelen (.358") it is 63.780 mm sq, and for .357 Magnum it's 62.570 mm sq in the GRT database. Try one or the other and see if that issue goes away. If it was me, and I wasn't sure, I'd stick with the .357 Mag dimension just for the sake of safety.


Originally Posted by gonehuntin
Give a communist a helicopter ride, he flies for an afternoon. Throw a communist out of a helicopter and he flies for the rest of his life.....



Joined: Nov 2008
Posts: 6,543
Campfire Tracker
Offline
Campfire Tracker
Joined: Nov 2008
Posts: 6,543
Originally Posted by Quickbeam
This is the message i get

Personally I would go to View/Change all units/imperial. Sometimes computer programs get confused when some of the settings are metric but others imperial which is the situation you have.



Swifty
Joined: Aug 2011
Posts: 88
Q
Member
Offline
Member
Q
Joined: Aug 2011
Posts: 88
I've tried several different entries from 63 to 65 and the error message remains. Changed all variables to metric, then imperial and still it remains. I did finally get to fire the gun for the first time over my chronograph and compare numbers with GRT.
GRT predicted 1790 fps and 3600 psi
Measured actual velocity was 1,500 fps and pressure too low to fireform to a sharp shoulder.

Changing effective barrel cross section between anything reasonable could not bring the numbers to agree. I'm working on every variable to make sure the parameters are accurate.

Joined: Dec 2021
Posts: 6
J
New Member
Online Content
New Member
J
Joined: Dec 2021
Posts: 6
GRT has been spot on for me with powders that have a high calibration...except for Vihtavuori N105 and 300 blackout subsonic loads. GRT overestimated velocity by > 200 fps.


Moderated by  RickBin, SYSOP 

Link Copied to Clipboard
CTV-TRX
Who's Online Now
616 members (10Glocks, 1234, 06hunter59, 1Akshooter, 160user, 69 invisible), 1,919 guests, and 1,154 robots.
Key: Admin, Global Mod, Mod
RR2/3-22

UDG-IP









Fish & Game Departments | Solunar Tables | Mission Statement | Privacy Policy | Contact Us | DMCA
Hunting | Fishing | Camping | Backpacking | Reloading | Campfire Forums | Gear Shop
Copyright © 2000-2022 24hourcampfire.com, Inc. All Rights Reserved.
 
Powered by UBB.threads™ PHP Forum Software 7.7.5
(Release build 20201027)
Responsive Width:

PHP: 7.3.33 Page Time: 0.063s Queries: 15 (0.003s) Memory: 0.9054 MB (Peak: 1.0336 MB) Data Comp: Zlib Server Time: 2022-10-05 19:30:08 UTC
Valid HTML 5 and Valid CSS