https://allgunstuff.co.za/community/reloading-methodology AllGunStuff Discussion Board en-US Mon, 15 Jun 2026 10:07:39 +0000 wpForo 60 https://allgunstuff.co.za/community/reloading-methodology/if-grt-on-linux-gives-problems Fri, 10 Apr 2026 10:22:54 +0000
The quickest and easiest way to get GRT working in Linux is to run it on a Windows VM in VirtualBox.

You can share the GRT data folder with the VM, so it is accessible directly.

I've got a Windows XP VM, running the Windows version of GRT. And a couple of other bits of Windows software that I use once in a while, for which there is no Linux equivalent.


]]> Reloading Methodology 414gates https://allgunstuff.co.za/community/reloading-methodology/if-grt-on-linux-gives-problems https://allgunstuff.co.za/community/reloading-methodology/how-to-add-a-new-powder-to-grt Fri, 10 Apr 2026 10:09:39 +0000
I've used the data from VV 24N as an entry point.

What is the process to true the powder data against measured velocity.

Google says :

Steps to Add a New Powder in GRT:
    Generate Data: Perform a 2x2x2x5 development run (2 calibers, 2 bullet weights, 2 charges, 5 shots each) over a reliable chronograph.
    Input Data: Open GRT and input your specific load data, including accurate bullet measurements and case volume.
    Use OBT (Optimal Barrel Time): Use the GRT OBT tool to match the pressure curve and burn rate to your actual measured velocities.
    Save as New Powder: Click on 'Create grt load file' after the OBT simulation produces accurate results to save the new powder in the user section.

I just want confirmation that the method works as advertised.


]]> Reloading Methodology 414gates https://allgunstuff.co.za/community/reloading-methodology/how-to-add-a-new-powder-to-grt https://allgunstuff.co.za/community/reloading-methodology/sus-tac-bullets Sun, 05 Apr 2026 09:51:21 +0000 I was given five of the HP tipped (metal tip ) in 180gr to try out
Looks to me to be a mono-metal - although it does not have any bands on the bullet body
It is a very long bullet 39.64mm but which I can use in / as a repeater without problems

When I came to use them I used GRT to work out a load - using all my measured data
I chose a low pressure load under 59,000

However when fired the cases exhibited high pressure and the velocities were much higher than indicated
I am not sure what is going on here ?

I have to use an additional two grs in the simulation to get to the velocity that was predicted - which has higher pressure and takes me above 63000psi

Perhaps the bullets being mono-metal exhibit higher pressure due to constriction in the barrel ?

The few loaded cartridges that were shot were however accurate
I did not carry on shooting when I noticed the much higher velocities

]]> Reloading Methodology Newton https://allgunstuff.co.za/community/reloading-methodology/sus-tac-bullets https://allgunstuff.co.za/community/reloading-methodology/bullet-jump-and-base-to-ogive Fri, 03 Apr 2026 23:16:41 +0000 Bullet manufacturers will (sometimes)  supply the length of the bullet
However what is really important is the dimension / length at which the ogive starts
After all it is at the ogive ( full diameter ) that the  bullet meets the rifling
and
This is where you measure "bullet-jump"
This is generally measured by ...BoT = Base to Ogive to give an indication of where the bullet will actually start engraving.
I am not sure if this information is provided - in a QL .bul file ?
I have discovered that I can actually load very long bullets ( as long as they fit in the magazine ) because a large part of the front of the bullet is NOT at ogive dimension - and my barrel / chamber has a long throat
This means that I can increase the load ratio without necessarily adding more powder ( pressure )

IF this information is supplied I would like to know where you find it ?
Rather than having to measure all the bullets manually


]]> Reloading Methodology Newton https://allgunstuff.co.za/community/reloading-methodology/bullet-jump-and-base-to-ogive https://allgunstuff.co.za/community/reloading-methodology/quickload-berger-bullets Wed, 01 Apr 2026 11:23:07 +0000 I see a few that I do not have in my current berger.bul file

]]> Reloading Methodology Newton https://allgunstuff.co.za/community/reloading-methodology/quickload-berger-bullets https://allgunstuff.co.za/community/reloading-methodology/explosia-lovex-powders Mon, 30 Mar 2026 22:31:04 +0000 ]]> Reloading Methodology Newton https://allgunstuff.co.za/community/reloading-methodology/explosia-lovex-powders https://allgunstuff.co.za/community/reloading-methodology/differences-between-ql-and-grt Thu, 26 Mar 2026 00:41:43 +0000 Simulations .. because there is no ACCURATE easy way to measure pressure - although it is possible to accurately measure velocity
Velocity and pressure are however not parametrically one to one linked !

My particular application is a bit different as my rifle has a very long throat - more than the total length of the magazine so I have to load long ie. you can get more powder in the case

Seeing as the easiest powders to get are the VV ( not Vryheids Vront ) I have been running simulations in the N555 / 560 / 160 burn rate - 5 powders are double base 1 powders are single base

They are all quite close differing on load ratio - how much you can stuff into a case
Seeing as powder is so hellishly expensive one tries to find a powder that works needing less

I have found that QL and GRT differ quite a bit in their simulation of these VV powders
( It is possible that my powder files are not 100% up to date ? )

However what have the maestros discovered - from real World experience - with the above powders
What is more accurate in load simulation .. QL or GRT ?

]]> Reloading Methodology Newton https://allgunstuff.co.za/community/reloading-methodology/differences-between-ql-and-grt https://allgunstuff.co.za/community/reloading-methodology/300-weatherby-brass-from-375-hh Mon, 23 Mar 2026 12:42:49 +0000
Anneal the 375 brass.

Apply case lube.

Size in one easy stroke to 300 H&H.

Check case length.

Ready for fireforming in 300 Weatherby.

Picture is 375 H&H flanked by formed 300 H&H cases.

]]> Reloading Methodology 414gates https://allgunstuff.co.za/community/reloading-methodology/300-weatherby-brass-from-375-hh https://allgunstuff.co.za/community/reloading-methodology/new-vs-fireformed-brass Mon, 23 Mar 2026 02:32:39 +0000
So far so good. They now return with spent cases, and I neck size them with a collet and reload the same load. What is going to change between new and fire formed brass?

1. Velocity decreases - the fireformed brass increases the size of the space in which the pressure builds up, resulting in lower presser and the need to add 0.1-0.3gr of powder to get it back on node.

2. Nothing - the pressure (and indirectly barrel time and velocity) is based on the size of the chamber, and since the brass thickness and chamber doesn't change size, there is no need to change anything.

3. Velocity increases - this seems counterintuitive, but the case expansion of new brass to fit the chamber absorbs energy. On fireformed brass, the pressure build up is more direct, because the brass does not need to expand in to the chamber, so all the energy is transferred to the bullet, and pressure is higher, therefore one needs to decrease the load by 0.1-0.3gr to stay on the node.

ChatGPT got a bit baffled by this, I think because a lot of guys with custom build competition rifles with tight chambers seem to get different results than commercially chambered rifles with high tolerances. 

Does anyone have some real world experience of this?
]]> Reloading Methodology Againstthegrains https://allgunstuff.co.za/community/reloading-methodology/new-vs-fireformed-brass https://allgunstuff.co.za/community/reloading-methodology/wet-tumbling Mon, 16 Mar 2026 01:19:32 +0000 I recently inherited a small jewellery tumbler
The tumbler looked like it could be used for wet tumbling - which I think is what it was designed for ?
So got hold of some stainless steel pin tumbling media
After a few attempts at finding the correct "recipe" cases are now coming out like new

I am amazed at the amount of - crud - that is cleared out
After an hour of tumbling the water is pitch black.

I just wonder what the effect is of shooting the same cases over and over again without any cleaning ?
Dry tumbler cleaning does NOT remove internal residue

Personally I would prefer to start each new reload with a case that is also "new" ...
One can always provide some lubrication for the bullets when at the stage of seating
]]> Reloading Methodology Newton https://allgunstuff.co.za/community/reloading-methodology/wet-tumbling