McGuire Ballistics, 338's!

[KH_Outdoors]

Starting a post here as I'm diving into testing some new monolithic hunting bullets from McGuire Ballistics!

The purpose is to get some general info out there since they're so new. I've had great luck with the McGuires in multiple rifles, cartridges, & calibers to date so I'm stoked to give these 338's a run!

The bullets to be tested are the 250 & 225 grain "Copper Rose" projectiles. 250's are up for pre-order now and the 225's are soon to be posted on the site, also for pre-orders.

I will be using two different rifles to do some basic load development and BC testing with. It will be a standard chambered 338 Norma for the 250's, and a 33 Sherman Magnum for the 225's.

Here's a pic for reference!

225 OAL = 1.755"

250 OAL = 1.925"

Stay tuned!

 

[KH_Outdoors]

First up, 338 Norma!

The Rifle:

Snowy Mountain Rifle built
Defiance Action
24" Proof 9.4 tw barrel
AG Alpine Hunter adj
Triggertech
MK5 5-25x56 scope
ARC Rings
Flatline ops level

Some pics for reference, this is all in a standard chamber that has optimal freebore for 300 Berger's (300 EH's @ 3.720" COAL). The COAL's posted are @ the lands.

250 gr CR's:

225 gr CR's:

 

[KH_Outdoors]

For the first round of testing I'm just looking to get a general feel for where safe pressures are, speeds, and if it likes one powder more so than another.

338 Norma/250 CR

Brass: Lapua 3x fired & meticulously prepped
Primer: Fed 215's
Powders: H1000, N565, RL26
Bullet: 250 CR seated .025" off the lands, 3.755" COAL

 

[huntinfool18]

Is there any rough estimates on BC numbers on these?

 

[KH_Outdoors]

Is there any rough estimates on BC numbers on these?

They are still to be determined right now, but after speaking with Sam the owner here's what I'm starting with based on his current testing.

Estimated BC

250 CR's: .830 (G1)

225 CR's: .600 (G1)

These are only rough starting points and to be finalized based on alot more testing.

 

[huntinfool18]

Those are some impressive numbers. I'll be looking forward to your testing updates.

 

[Coyote Shadow Tracker]

First up, 338 Norma!

The Rifle:

Snowy Mountain Rifle built
Defiance Action
24" Proof 9.4 tw barrel
AG Alpine Hunter adj
Triggertech
MK5 5-25x56 scope
ARC Rings
Flatline ops level

Some pics for reference, this is all in a standard chamber that has optimal freebore for 300 Berger's (300 EH's @ 3.720" COAL). The COAL's posted are @ the lands.

250 gr CR's:

View attachment 567649

225 gr CR's:

View attachment 567650

Is that 1:9.4 twist going to be enough? Curious I have a few Krieger .338 with 35" in 1:9 on order for our .338LMAI. May chamber one in a .338NM.
Thanks

 

[KH_Outdoors]

Is that 1:9.4 twist going to be enough? Curious I have a few Krieger .338 with 35" in 1:9 on order for our .338LMAI. May chamber one in a .338NM.
Thanks

Great question!

The 250's are going to be listed as a 1:9 minimum. And the 225's will be listed as a 1:10 minimum.

Initial testing with the 250 grainer's were done with 1:9.3 & 1:9.4 twist barrels and they in fact did stabilize.

That said, mono's typically like being spun hard. I just ordered an 8 twist Carbon Six barrel to have a custom throated 338 Norma Barrel spun up. Guessing that will be done this fall for a winter project.

 

[KH_Outdoors]

Those are some impressive numbers. I'll be looking forward to your testing updates.

They certainly are! I'm guessing they'll be pretty close to that when it's all said and done.

 

[Coyote Shadow Tracker]

Great question!

The 250's are going to be listed as a 1:9 minimum. And the 225's will be listed as a 1:10 minimum.

Initial testing with the 250 grainer's were done with 1:9.3 & 1:9.4 twist barrels and they in fact did stabilize.

That said, mono's typically like being spun hard. I just ordered an 8 twist Carbon Six barrel to have a custom throated 338 Norma Barrel spun up. Guessing that will be done this fall for a winter project.

Thanks
Awesome!!!

 

[KH_Outdoors]

Thanks
Awesome!!!

Absolutely!

 

[FEENIX]

Starting a post here as I'm diving into testing some new monolithic hunting bullets from McGuire Ballistics!

The purpose is to get some general info out there since they're so new. I've had great luck with the McGuires in multiple rifles, cartridges, & calibers to date so I'm stoked to give these 338's a run!

The bullets to be tested are the 250 & 225 grain "Copper Rose" projectiles. 250's are up for pre-order now and the 225's are soon to be posted on the site, also for pre-orders.

I will be using two different rifles to do some basic load development and BC testing with. It will be a standard chambered 338 Norma for the 250's, and a 33 Sherman Magnum for the 225's.

Here's a pic for reference!

225 OAL = 1.755"

250 OAL = 1.925"

View attachment 567646

Stay tuned!

I am looking forward to your test results on the 250, and I hope this thread stays on course.

 

[KH_Outdoors]

I am looking forward to your test results on the 250, and I hope this thread stays on course.

I'll get them up real time for ya!

Just loaded up the powder charge ladders this afternoon.

Should get a break in the weather this week to go run them

Also pre-ordered a batch of 100 to keep the testing dialog going here. When they get enough pre-orders in they'll spin them up.

 

[Idaho Trecker]

I'm running the 250 grain on my 33 nosler and haven't had much time to do much for bc testing between getting ready for bear hunting and shooting a NRL Hunter match.

First outing shooting paper was 671 yards and came up about half moa low. From my second outing shooting paper with only 2 rounds at 1071 yards I'm running a .350 g7. This bc seemed to be slightly high for me so far but I need more rounds to out on paper at distance under those perfect dawn conditions. Both outings I seemed to be the half moa low. Also running a 9.5 twist And at 3000' where I'm at I'm still technically stable with a 1.5 sg.

Next week I may get time to shoot again unless I run out of bullets first bear hunting and busting rocks.