Custom 300 Norma Magnum Barrel

[Relja]

Hello All,

As per the thread title I am looking at getting a custom 300 Norma magnum barrel for my Desert Tech SRSA2.

I wanted to confirm what recommended Barrel length and twist rate would be recommended by the group and also how heavy of a barrel to get.

I am hoping to shoot as far as 2600 metres with the barrel and want it heavy enough to hopefully keep the barrel as cool as possible and also keep the weight of the rifle to a manageable point for extended shooting days.

I know that there are available kits from Desert Tech, but I would rather get a custom barrel as I think it will be slightly more accurate and increase the weight of the rifle to decrease some of the recoil. As with my 338 lapua kit shooting a 100 rounds in a day left me bruised and made me wait quite a bit for the barrel to cool.

I was thinking minimum 26" barrel (not sure what twist rate) or how heavy a barrel to grab.

Was going to go either InSite arms or IBI as I am up in canuckistan.

 

[gnochi]

Any reason not to get a ~32” truck axle?

I think Insite Arms deals with Bartlein; given the cost of the system and how hot 300NM runs it’s definitely worth the hassle of getting the new MOD400BB steel for the blank. Probably a 1:7 twist for monos, or a 1:9-8.25 gain twist for jacketed, depending on velocity/bullet/altitude/etc. and with a custom order might as well go left handed twist for a better recoil impulse and partially counteracting spin drift and Coriolis. If you wanted to get fancy, I mean.

 

[JB.IC]

Bartlein barrel
28-30” finish length
Max barrel OD(whatever that is) for 8” then taper to 1.125” at the muzzle
8-twist 5R
245 Berger Elite Hunter

 

[Relja]

Any reason not to get a ~32” truck axle?



I think Insite Arms deals with Bartlein; given the cost of the system and how hot 300NM runs it’s definitely worth the hassle of getting the new MOD400BB steel for the blank. Probably a 1:7 twist for monos, or a 1:9-8.25 gain twist for jacketed, depending on velocity/bullet/altitude/etc. and with a custom order might as well go left handed twist for a better recoil impulse and partially counteracting spin drift and Coriolis. If you wanted to get fancy, I mean.


For the truck axle, kind of wanted to still keep it somewhat movable and most of the guys in the course I was on were using 26" Cadex rifles. I have contacted InSite. So will see if they have those Bartlein blanks.

What is the difference between 1:9 and 1:8.25 as I think I will most likely either be using Hornady or Berger bullets.

As for left hand twist I'm not going too fancy lol.

 

[Relja]

Bartlein barrel
28-30” finish length
Max barrel OD(whatever that is) for 8” then taper to 1.125” at the muzzle
8-twist 5R
245 Berger Elite Hunter

Any recommendations for other bullets as I don't think I will be hunting with this bullet.

Probably looking at Hornady or Berger. Maybe Lapua

 

[Matt_3479]

Take a look at KS arms. Between me and the guys I know we have 8 or so barrels and every single one of them are simply incredible. I’ve dealt with one of the two your looking at and while it was.. okay I’m not 100% sure if I’ll be going back. Where as I’ve dealt with ks on 3-4 occasions now ans have been 100% satisfied with customer service, communication and product!! They clean up really quick, and all except 1 has been pretty fast! Not that the one is slow it’s just average that’s it. They have all produced super well with 3 rifles, (2 prs and 1 hunting) have all shot .25” super easy

 

[Relja]

Take a look at KS arms. Between me and the guys I know we have 8 or so barrels and every single one of them are simply incredible. I’ve dealt with one of the two your looking at and while it was.. okay I’m not 100% sure if I’ll be going back. Where as I’ve with ks on 3-4 occasions now ans have been 100% satisfied with customer service, communication and product!! They clean really quick, and all except 1 has been pretty fast! Not that the one is slow it’s just average that’s it. They have all produced super well with 3 rifles, (2 prs and 1 hunting) have all shot .25” super easy

Do they do pre-fits for Desert Tech? Honestly have never heard of them before this.

 

[Reload10]

Is this them?

K.S. ARMS LTD

www.ksarms.com

 

[Matt_3479]

Do they do pre-fits for Desert Tech? Honestly have never heard of them before this.

Is this them?

Just send them an email. There still updating there website on the barrels/prefits for other actions.

K.S. ARMS LTD

www.ksarms.com

Yes it is. I have multiple benchmarks, multiple bartleins, and now a few KS. While they all shoot well, the KS are preforming awesome.

 

[dgheriani]

I have a 1:9tw 29.5" Krieger .300NM in Insite's "pet" contour (I think it's a heavy varmint/mtu hybrid) that they spun up for me. It's an absolute laser with Berger 220 LRHTs and N570. I haven't taken it out past 1830 yards yet but routinely shoot it to 1600. You definitely can't go wrong with a Krieger (or Bartlein) spun up by Insite.

 

[Dogtown]

26" is pretty standard, but if you're hoping to get to 2600m you should try to go longer. I have a 28" barrel (1.045" straight contour for SRS) that allows me to push 210-230gr bullets in the 3000-3100fps range, but an extra 4+ inches will give you an extra 100+ fps that could make a difference with heavier bullets. 1:8 twist is fine for bullets in that same class, but if you plan to go heavier then obviously go with a 1:7. I've become a big fan of the Seneca solids with this cartridge, specifically the 212gr solid in this barrel. Combined with N570 I'm getting a safe 3075fps which will stay supersonic to about 2200 yards. For comparison, I have on order a 32" 1:7 barrel now that I plan to shoot the 241gr Seneca solids around 3000fps, which should stay supersonic to about 2800 yards.

I hardly shoot my .338LM Improved barrel anymore.

 

[gnochi]

What is the difference between 1:9 and 1:8.25 as I think I will most likely either be using Hornady or Berger bullets.

Specifically it would start at 1:9 at the chamber and speed up to 1:8.25 at the muzzle - slightly less bullet deformation as it enters the rifling means more consistent flight. There’s a long thread on gain twist here, particularly in left hand:

Post in thread 'Left-Hand Gain Twist'
https://www.snipershide.com/shooting/threads/left-hand-gain-twist.6949483/post-7919534

Left handed twists make it much more comfortable to shoot heavy bullets fast as a right handed shooter. If nobody has a MOD400BB blank sitting around you’re waiting a while anyway and might as well get exactly what you want

 

[JB.IC]

Any recommendations for other bullets as I don't think I will be hunting with this bullet.

Probably looking at Hornady or Berger. Maybe Lapua

The 245gn Elite Hunters can be used for target shooting. They have a really high BC which is why I mentioned them.

The 220 LRTH or 230 Hybrids from Berger are also good options. I would opt for the 220 LRTH between the two because they have about the same BC as the 230 hybrids but since they’re a lighter bullet, they can be shot faster. Win win.

the Hornady 250 ATIPs would be another high BC option as well.

Also for the 245 and 250gn jacketed bullets an 8 twist is the fastest you need. The 220 and 230gn jacketed bullets a 9 twist is the fastest you’d need. However, an 8 twist can be used for all four jacketed bullet weights just fine.