GRT Questions

[Longtrain]

I ran a trial version of CrossOver in order to run GRT on my MacOS, it works pretty well.

I played around loading my standard Dasher load, with Tungsten Disulphide (WS2) coated 108 Bergers, jumped .010”, N140 and Russian Tula 556M primers. I don’t see an entry area for primers or someway to tell the software that my bullets are coated.

My load, in Lapua BR formed brass show absolutely no pressure signs and I have been using that load for a couple of years with no issues.

So, GRT tells me that my load is over pressured, of which I show no evidence. Is there a data entry for primer choice and whether the bullet is coated? Thanks.

 

[jelenko]

Click on Star next to 'Initial Pressure'. A pop up provides an option to select magnum vs standard primer.

 

[David Christian]

Two points I would consider. Did I entered my exact reamer print and brass dimensions? Did I record actual ladder test data to calibrate my load?

 

[dstoenner]

If you don’t run an obt to curve fit your barrel and case to the correct powder values you only have a guess of where you are.

David

 

[Longtrain]

Thanks for the advice, it helped. Playing with the program as I get time. Interesting for sure.

 

[dstoenner]

Here is a thread I started on how to use GRT to get a load:

How to get a load in 50 bullets with Gordon's Reloading Tool (GRT)

There have been a few threads on here about GRT. I have been using it for over 2 years now. As an electrical engineer, I am used to simulating systems to see the response. GRT is just exactly that but the "trick" is how to coax it into giving you a good answer. That took me some time to...

forum.accurateshooter.com

This is how I get good values out of GRT

David

 

[jxb]

@Longtrain "So, GRT tells me that my load is over pressured, of which I show no evidence."

One thing I'm seeing talked about more and more lately is how some of the tough brass out there can lead to masking pressure signs until you're way over pressure like 20k over before seeing signs. Keeps coming up with Alpha brass, but I'm thinking it may be just as true with others.

Anyhow, to me it's worth keeping in mind as a possibility. This of course assumes you've double checked GRT for that load to assure you have all entries in and correct. A person likely could get someone to sanity check your same load in Quickload as another check.