Gordon's Reloading Tool - Lapua 144 grain MaxRange Target (GB582)

thirdeye462

thirdeye462

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Hello collective wisdom,

I'm shooting 6.5 PRC out of a 26" Bartlein barrel, about to begin hand loading for long range precision target, and have all my components/gear except for powder and bullets. I will be using Lapua brass and CCI BR-2 primers. I will likely choose the Lapua MaxRange 144s for hand loading. I may start with VV N565, Retumbo, and H1000.

I've been studying Gordon's Reloading Tool for the past year or so and have a reasonable grasp of the program and how it works. Because the software is not being updated anymore, the new Lapua Maxrange 144 grain bullets are not in the bullet database.

Someone over at Sniper's Hide shared a bullet file for the Maxrange 144s so that others can upload into their copy of GRT: https://www.snipershide.com/shootin...r-maxrange-target-gb582.7276570/post-12449067.

Interestingly, they used 143.5 grains in the file, and not 144. I do not know why nor whether that matters (it seems that it does). It got me thinking...

Has anyone on here been shooting the Maxrange 144s and built a bullet profile for them in GRT? If so, does your file match the one over at Sniper's Hide or is it different?

Thanks,
 
thirdeye462 said:
Hello collective wisdom,

I'm shooting 6.5 PRC out of a 26" Bartlein barrel, about to begin hand loading for long range precision target, and have all my components/gear except for powder and bullets. I will be using Lapua brass and CCI BR-2 primers. I will likely choose the Lapua MaxRange 144s for hand loading. I may start with VV N565, Retumbo, and H1000.

I've been studying Gordon's Reloading Tool for the past year or so and have a reasonable grasp of the program and how it works. Because the software is not being updated anymore, the new Lapua Maxrange 144 grain bullets are not in the bullet database.

Someone over at Sniper's Hide shared a bullet file for the Maxrange 144s so that others can upload into their copy of GRT: https://www.snipershide.com/shootin...r-maxrange-target-gb582.7276570/post-12449067.

Interestingly, they used 143.5 grains in the file, and not 144. I do not know why nor whether that matters (it seems that it does). It got me thinking...

Has anyone on here been shooting the Maxrange 144s and built a bullet profile for them in GRT? If so, does your file match the one over at Sniper's Hide or is it different?

Thanks,
Click to expand...
Not sure what it is you are questioning. A ½ grain difference between measured and nominal bullet weight is not unusual.

Have you weighed any of those bullets? I expect the 143.5 grain measurements would be an average weight of a number of bullets and whoever would do that has some level of competence over a person who simply assumed 144 gr was exactly right on.
 
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I'm just looking to verify data at the moment. That particular bullet file was the only one I discovered for the 144 MaxRange and am curious if others created their own profile for this bullet. (Now that I think of it, I'll probably sign-up on the GRT Discord channel and inquire about this there, too.)

The 143.5 grains-as -average make sense to me, too. But when you look at what's in GRT already, you see nominal bullet weight values listed in the bullet database. I have not gone so far to see whether there's a difference between the description of the bullet profile and what the actual "gmass" value is in the same profile.

In any event, yes, once I acquire these guys, I'll be weighing, measuring, and sorting them with the expectation that there's gonna be some kind of variance.
 
I've found, in both GRT, as well as QL, that bullet measurments, both length & weight, have to be adjusted. The measuremental differences also include differences in BT length, as well as their small diameters. Since these are, presumably, simply manufacturing tolerances between lots, I just adjust for it, save the data & move on.

A bigger problem is that both programmes lack any adjustment for primers, as well as adjustments for bullets' bearing surface, which will effect pressures and, as a result, velocity, and ultimately, trajectory, although GRT does allow you to adjust for a bullets' design characteristics, which QL does not. Adding changes to the programmes to adjust for primer & bearing surface are well above my pay-grade, so I point them out as an observation only.

Once you become familiar and comfortable with GRT, you can adjust a powder's parameters, after you know what you are doing & have the chronograph data to confirm your adjustments. You can also do it with QL, but the process is more involved. [If NOT, then leave it TF alone!!!]
 
jamesharrison said:
I've found, in both GRT, as well as QL, that bullet measurments, both length & weight, have to be adjusted. The measuremental differences also include differences in BT length, as well as their small diameters. Since these are, presumably, simply manufacturing tolerances between lots, I just adjust for it, save the data & move on.

A bigger problem is that both programmes lack any adjustment for primers, as well as adjustments for bullets' bearing surface, which will effect pressures and, as a result, velocity, and ultimately, trajectory, although GRT does allow you to adjust for a bullets' design characteristics, which QL does not. Adding changes to the programmes to adjust for primer & bearing surface are well above my pay-grade, so I point them out as an observation only.

Once you become familiar and comfortable with GRT, you can adjust a powder's parameters, after you know what you are doing & have the chronograph data to confirm your adjustments. You can also do it with QL, but the process is more involved. [If NOT, then leave it TF alone!!!]
Click to expand...
Thanks, jamesharrison!

Yes, I remember reading somewhere that the Maxranges have a longer bearing surface compared to the Berger 144s. Some have mentioned that, because of this, they saw pressure signs presenting earlier in ladder-pressure testing. I'm nowhere near messing with powder values, so your advice is well taken! Lol.


Btw, the GRT Discord server mentioned that the 143.5 grain value in that projectile file is indeed an average, measured across 10 bullets :) Good to know. I think I'll up my sample rate once I get box to see what I'm dealing with.
 
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Don't forget to also check their lengths.

Forgot to mention in my original post that the reason they're listed as 143.5 gr. is that Lapua, like all European bullet makers, uses & manufactures to grams, NOT to the American standard of grains. Convert 9.3 grams & what do you get? 143.5209 grains.

On all of my old Norma 6.5mm RNSP Tombac jacketed bullet boxes, there is a sticker on the side of the boxes that says 156 grains. If you remove the sticker, it says 10.1g / 155.6 gn. If you convert 10.1 grams, you get 155.8668 grains. Same thing with my Norma & Sako 8mm bullet boxes. A sticker says 196 grains, but underneath, it says 12.7 g[rams]. Convert 12.7 grams to grains & you get 195.991 grains.
 
jamesharrison said:
the reason they're listed as 143.5 gr. is that Lapua, like all European bullet makers, uses & manufactures to grams, NOT to the American standard of grains. Convert 9.3 grams & what do you get? 143.5209 grains.
Click to expand...

Welp, that little observation was so obvious I didn't even see it! Lol. Thanks again, James! Didn't even think about the metric/imperial conversion at play here, but it makes sense. It also shows that if that measured value of 10 bullets from that lot were 143.5, Lapua's tolerances are tight. I look forward to measuring out the lot I will eventually purchase.
 
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