Terminus Zeus

[ShevchenkoT]

Hello. I'm looking at doing my first custom rifle build. The plan is to build a 338 lapua and 300Norma Magnum. Looking for any advice I can get. So far, all I've decided is that I want to go with a Terminus Zeus action QC.

Which brings me to my question. What dimension bolt face do I need for a 338 lapua and 300nm?

Also any recommendations for a barrel (manufacturer, lenth, twist, bore contour)? How reliable is the quick changeable system?

 

[_Windrider_]

Hello. I'm looking at doing my first custom rifle build. The plan is to build a 338 lapua and 300Norma Magnum. Looking for any advice I can get. So far, all I've decided is that I want to go with a Terminus Zeus action QC.

Which brings me to my question. What dimension bolt face do I need for a 338 lapua and 300nm?

Also any recommendations for a barrel (manufacturer, lenth, twist, bore contour)? How reliable is the quick changeable system?

You’ll need the magnum and lapua bolts to switch between those calibers. As far as barrels I always recommend bartlein. @Frank Green can give you the best recommendation on the specifics. The QC system is ultra repeatable. You will not be disappointed.

 

[kthomas]

You’ll need the magnum and lapua bolts to switch between those calibers. As far as barrels I always recommend bartlein. @Frank Green can give you the best recommendation on the specifics. The QC system is ultra repeatable. You will not be disappointed.

Lapua bolt face only to use both the requested cartridges.

 

[kthomas]

Length and contour is very much user preference. Longer for more velocity, shorter for less length (duh) and less weight.

For a .300NM, the sweet spot is probably around 28". You can go 26", but you don't really see many barrels shorter than that for the cartridge. 30"+ makes for a pretty long and heavy rifle, if that matters to you. Most people stick with pretty heavy contours M24/40 to 1.25" straight. Mine is a ~29" heavy varmint.

For twist rate, go 1:9 or 1:10. Some people get away with faster twists (1:8), but also lots of reported issues out there, including from the military with such a fast twist.

Edit to add: all the above is in regards to .300NM. I have no personal experience with the .338LM.

 

[_Windrider_]

Length and contour is very much user preference. Longer for more velocity, shorter for less length (duh) and less weight.

For a .300NM, the sweet spot is probably around 28". You can go 26", but you don't really see many barrels shorter than that for the cartridge. 30"+ makes for a pretty long and heavy rifle, if that matters to you. Most people stick with pretty heavy contours M24/40 to 1.25" straight. Mine is a ~29" heavy varmint.

For twist rate, go 1:9 or 1:10. Some people get away with faster twists (1:8), but also lots of reported issues out there, including from the military with such a fast twist.

Plus the military made the mistake of using the 300gr 338 when they should have gone with 250’s or maybe the 285

 

[kthomas]

Plus the military made the mistake of using the 300gr 338 when they should have gone with 250’s or maybe the 285

I was actually speaking specifically about the .300NM. I don't have any experience with the .338LM, I should've been more clear in your post.

But from what I understand I believe you are right. I've heard that the lighter projectiles work better from the .338LM.

 

[ShevchenkoT]

The main purpose is military sniping bc I'm Ukrainian sniper. So, the rifle with barrel length more than 26", I think, is less convinient.

 

[JustSendit]

Plus the military made the mistake of using the 300gr 338 when they should have gone with 250’s or maybe the 285

I heard Frank saying this: what’s wrong the 300gr projectiles?

 

[_Windrider_]

I heard Frank saying this: what’s wrong the 300gr projectiles?

Speed is king.

 

[JustSendit]

Speed is king.

Moving earth helps for corrections.

 

[Bravo6niner]

Speed is king.

I think a guy needs to keep in mind that Frank is usually shooting factory guns and factory ammo. A 338LM with a 28-30” barrel and reasonable hand load using 300gr bullets will start to edge out a 250gr projectile/load that Frank is typically shooting.

That said a 285ish grain berger lrht type bullet would be freaking awesome.

 

[JustSendit]

I think a guy needs to keep in mind that Frank is usually shooting factory guns and factory ammo. A 338LM with a 28-30” barrel and reasonable hand load using 300gr bullets will start to edge out a 250gr projectile/load that Frank is typically shooting.

That said a 285ish grain berger lrht type bullet would be freaking awesome.

Yeah I think the purpose of the MSR was long range engagements, it’s heavy and cumbersome, kind of served a specific role. Which with the 300gr it did well, super high BC, lots of splash. Plus the time the rifle and bullet was selected, there were little less great options available.

It’s the military and it’s a civilians opinion on what the military selects. The military will never get it all the way right and a random civilian will always know what would have been so much better. Both things are true lol..

 

[_Windrider_]

Tools in the toolbox. If it were me I’d shoot the 250’s in calm to medium winds and step up to 285’s or 300’s in medium to high winds. Medium light and high are subjective. Also for the same exact weight I can carry 6 5 round mags of 250’s compared to 5 mags of 300’s. Also the mission should dictate the rifle caliber and bullet to use. Something the mil doesn’t really factor in. You get a one side fits all which is why they ultimately probably went with the 300.

 

[Bigrederic]

I am actually having another 300 NM built right now, but this time in left hand and in chambered in the improved variety in a 27" Mod BB MTU with a 1-8.5 twist .

My current gun is a 28" 300 NM in 1-9 and a m24 barrel, gun is a hammer with 225s, it is a bloody lazer beam. But I wanted a left handed gun to shoot left handed so here we are, and I also wanted to be able to shoot the 250 Atips.

Old rifle is a Defiance action with 30 MOA rail and a with a PMii, New gun is a Terminus Zeus and it has a 20 MOA rail and a PMii mounted in a Eratac adjustable inclination mount.

The action you picked is a great action, both rounds you are talking about use the Lapua bolt face, overall the rifle should be awesome if you use the right components and a good smith.

​

 

[ShevchenkoT]

Relatively Zeus, my concern is 1,062" thread tenon. Is the barrel enough for 338lm?

 

[Bigrederic]

Relatively Zeus, my concern is 1,062" thread tenon. Is the barrel enough for 338lm?

Joel recommended the full thread version to me.

 

[ShevchenkoT]

How does it work?

 

[Bigrederic]

How does it work?

It has threads on the full barrel shank to give it more purchase, instead of the unthreaded portion on the forward part for the set screws and it torque on with a action wrench and barrel vise.

 

[harry_x1]

I regularly shoot 338 Lapua from my AI AXMC and hopefully some of my experience might be of some use.

I have shot 250 grain and 300 grain berger elite hunter bullets both from a 26 inch as well as a 20 inch AI barrell (I believe they use bartlein blanks).

In my experience 300 grain bergers shoot way better than 250 grain bullets. The 250 grains were an improvement over 6.5 creedmoor and I did not have to hold as much wind, but it was still a significant wind hold anytime I was shooting in windy conditions or anytime distances were beyond 1000 yards. I was really surprised how much less wind a 300 grain bullet requires vs a 250 grain. Those additional 50 grains seem to make a non linear diff. From that time on, I have never gone back to 250 gr..in fact I have a load of 250 grain Bs lying around and I just could never gather enough enthusiasm to load and shoot them.

Regarding barrell lenght, I have noticed that a shorter barrell offers better harmonics and other conditions being equal, it tends to be a more precise shooter as well. My 20inch barrell is a laser beam uptill 300 yards and I frequently get single hole groups at that distance. From 26inch barrell with a 91 grain H1000, I get 2774 muzzle velocity. With 20 inch barrell I unfortunately have forgotten the muzzle velocities I got. But can safelly approx it to be in the range of 2600fps+. That is plenty of velocity for a 300 grain bullet to a consitent shooter at a mile. I usually get 9/8 out of 10 shots at a 1550 yard 2x2' steel. My next project is to actually build a shorter barrell (18 or 20 inch) lighter weight 338 lapua mag gun. I am kind of a convert to shorter barrells as they tend to give better accuracy with limited impact on MVs (provided you handload). Additionally I beleive the higher BCs from heavier bullets outplay MVs. Just my 2 cents. There are people who might have had a diff experience or might know more, but just wanted to share my leanings here.