37XC Build

[Rocketmandb]

Posting this here because I think the bolt action sub forum is not so much about ELR.

I have officially started my 37XC build. This is my first time going bigger than a .30 cal, so I'll be documenting the whole thing in a series of videos, which I'll post here.

Going with:

Action: Bat CT octagonal action, single shot, integral 40 moa rail, nitrided action, stainless bolt (4-6 months).
Stock: McMillan A6 Supermag stock - fiberglass, "Sniper" fill, clamp cheek riser, Anschutz rail, 3-way adjustable butt plate (6-8 months).
Trigger: Geissele Super 700
Barrel: EDIT: Benchmark 5 grooves, 1-8 twist, Varmint Style with straight cylinder then straight taper - Cylinder 1.47" to match the action for 5" length, then straight taper to 1.1" muzzle
Brake: EDIT: T5 Terminator

I've already got the dies, 200 brass, reamer

 

[badassgunworks]

Go with pierce action 1/2 the wait time . go with ks barrels in canada. Better barrel then bartline and only a 3 week wait and way cheeper as well.

 

[Matthew488]

I went with a Terminator T5 muzzle brake on my 375BAS. Very happy with it and recently put a T4 on my 338LM.

 

[Rocketmandb]

Go with pierce action 1/2 the wait time . go with ks barrels in canada. Better barrel then bartline and only a 3 week wait and way cheeper as well.

I looked at both (KS based on your recommendation in another thread). The long pole in all of this is the stock. Wait times for everything else are immaterial since I'll get all the other components before the stock is ready. The only thing I've ruled out due to wait times is using Bartlein as the barrel provider because it's currently at 9 months+.

 

[Rocketmandb]

Barrel ordered today (Benchmark 1-8, 31") and @jasent parted with a T5 Terminator that he sent my way as the brake. Now all the exciting stuff is done for a while.

 

[jasent]

I think you’ll be happy with the benchmark

 

[Steel head]

I think you’ll be happy with the benchmark

Did you get your 37XC sorted out?

 

[jasent]

Did you get your 37XC sorted out?

I burned it out. I got a great deal on 350 smk’s and shot them all lol. Went 1050ish rounds. My barrel just could not do solids. Tried a few and had major pressure so just stuck with smk’s. That rifle is for sale now with the 338 barrel on it. Working on a 416 barret build now. You interested in 37XC dies or reamer?

 

[Rocketmandb]

@jasent what did you use for ammo boxes for the 37XC? The 375 CheyTac boxes I'm finding are on the cusp of being too short, not to mention a little large diameter. Nothing 338 looks like it will work.

 

[Yerman]

@jasent what did you use for ammo boxes for the 37XC? The 375 CheyTac boxes I'm finding are on the cusp of being too short, not to mention a little large diameter. Nothing 338 looks like it will work.

Check these guys out.

DNA Custom Engraving, Ammo Cases, Reloading, Promotional, Trophies

Custom Ammo Cases, Reloading, Promotional, Trophies, Tumblers, Signage, Pelican, Big bore, Exotic, Hardwoods, Custom Woodworking, Cutting Board, Wine, Cheese, Serving, Platters, Zebrawood, Bubinga, Wenge, Walnut, Maple, Texas, Handmade, Unique, Creedmoor, Cheytac, Barrett, bmg, nosler, Sherman...

www.dnacustomengraving.com

 

[7mmShooter]

I burned it out. I got a great deal on 350 smk’s and shot them all lol. Went 1050ish rounds. My barrel just could not do solids. Tried a few and had major pressure so just stuck with smk’s. That rifle is for sale now with the 338 barrel on it. Working on a 416 barret build now. You interested in 37XC dies or reamer?

What's your reasoning for stepping up to the Barrett vs just putting a new barrel on the XC Jasen, get sick of the Savage action?

 

[jasent]

@jasent what did you use for ammo boxes for the 37XC? The 375 CheyTac boxes I'm finding are on the cusp of being too short, not to mention a little large diameter. Nothing 338 looks like it will work.

I never did find a box that worked well. I improvised with a lapua case but could not close the lid. Was a pain!!! Ended up using sleeves like you see on the buttstocks of hunting rifles in a carry bag. That was better

What's your reasoning for stepping up to the Barrett vs just putting a new barrel on the XC Jasen, get sick of the Savage action?

I like the savage. My rifle was a test rifle to see if I liked the 375 or if I wanted more......I want more

 

[7mmShooter]

I figured that was probably the case... The 416s definitely provide more target feedback

 

[Rocketmandb]

I never did find a box that worked well. I improvised with a lapua case but could not close the lid. Was a pain!!! Ended up using sleeves like you see on the buttstocks of hunting rifles in a carry bag. That was better

I have an (expensive - slightly) idea. I'll post it here if it will work decently well.

 

[Steel head]

I burned it out. I got a great deal on 350 smk’s and shot them all lol. Went 1050ish rounds. My barrel just could not do solids. Tried a few and had major pressure so just stuck with smk’s. That rifle is for sale now with the 338 barrel on it. Working on a 416 barret build now. You interested in 37XC dies or reamer?

I just started putting together a 338, Baby steps.

 

[Jimmy D in AK]

Check these guys out.

DNA Custom Engraving, Ammo Cases, Reloading, Promotional, Trophies

Custom Ammo Cases, Reloading, Promotional, Trophies, Tumblers, Signage, Pelican, Big bore, Exotic, Hardwoods, Custom Woodworking, Cutting Board, Wine, Cheese, Serving, Platters, Zebrawood, Bubinga, Wenge, Walnut, Maple, Texas, Handmade, Unique, Creedmoor, Cheytac, Barrett, bmg, nosler, Sherman...

www.dnacustomengraving.com

Inflection Ammo cases= awesomeness

 

[hohlspitz]

Infliction Ammo cases= awesomeness

It's Inflection:

https://www.inflectionde.com/produc...stem-100-round-4-5-max-oal-standard-cartridge

Be sure to read the description since the SKB case only allows shorter ammo length.

Condition 1 Case.
The kit includes a Condition 1 #075 case. This case is waterproof and dust tight with trigger relase latches and a rubber snap down handle.



SKB Case Option.

The kit includes a SKB 1209-4 case. This case is waterproof and dust tight with trigger relase latches and a rubber snap down handle. The SKB option is 0.75" shorter making the Max OAL of 3.75"

 

[Rocketmandb]

Got word that my stock is ready, so should have it in a week or so.

Also, just ordered a March Genesis 4-40 for this build and got in 300 Warner Flatlines today.

ELR ain't cheap.

 

[Steel head]

Got word that my stock is ready, so should have it in a week or so.

Also, just ordered a March Genesis 4-40 for this build and got in 300 Warner Flatlines today.

ELR ain't cheap.

No it isn’t!

 

[Rocketmandb]

Stock arrived today.

 

[Rocketmandb]

Update:

- Still waiting on my barrel and action.
- March scope is in - and still in the box
- Called BAT today and was happy to hear that the action is done, just waiting to be deburred. Then it goes out for the finish. Probably early January.

Hopefully I get this build done before fire season starts so I can take it out to the hills and stretch it out.

 

[babyguppy]

you still waiting on barrel and action? or should I ask this question in another 6 months

 

[Rocketmandb]

you still waiting on barrel and action? or should I ask this question in another 6 months

Action is at FFL. Just the barrel now, so maybe 3 months?

Actually, I did call and they said it was just waiting on rifling. As I'm finding with pretty much everything as you go bigger, it's not standard for most suppliers, so everything takes longer.

 

[Rocketmandb]

you still waiting on barrel and action? or should I ask this question in another 6 months

I just got the tracking # on the barrel...

 

[disky1]

What happened with this build? Interested to hear what the finished product is like

 

[Rocketmandb]

What happened with this build? Interested to hear what the finished product is like

Some slight delays. Thought I was going to take delivery this weekend, but it turns out the smith is coming to my area next week, so will be bringing it.

The only issue is that the ejection port doesn’t line up with the opening on the stock just right, which is annoying. I’m going to look at it when he delivers to see if I need to work it. It’s a bummer because the stock manufacturer had the drawings and, in the pictures at least, it’s noticeable. The smith said it doesn’t impact function, but I just need to see it in person.

 

[badassgunworks]

Why cant you gunsmith fix it. Must be a lago gunsmith . Most quality smith would fix the stock port area and make it perfect and would not even tell you about it.

 

[Rocketmandb]

Why cant you gunsmith fix it. Must be a lago gunsmith . Most quality smith would fix the stock port area and make it perfect and would not even tell you about it.

He can, but I want to look ok at it. Also need to get the paint, etc.

 

[Taylorbok]

Why cant you gunsmith fix it. Must be a lago gunsmith . Most quality smith would fix the stock port area and make it perfect and would not even tell you about it.

That's a bold strategy Cotton, let's see if it pays off for 'em

 

[Rocketmandb]

I'm getting over some food poisoning from Friday, so not feeling up to doing too much rifle related stuff, but I picked up my rifle yesterday evening.

This is my first foray into larger rifles/calibers. For those thinking about getting into it, be ready for very limited overlap with existing equipment. What's wrong with the first pic below? See anything out of whack with the gun vise? Yep, the rifle won't fit into it.

A couple pics:

 

[disky1]

If your not feeling up to it id take that rifle and test it for you.

Looks awesome.

 

[babyguppy]

I'm getting over some food poisoning from Friday, so not feeling up to doing too much rifle related stuff, but I picked up my rifle yesterday evening.

This is my first foray into larger rifles/calibers. For those thinking about getting into it, be ready for very limited overlap with existing equipment. What's wrong with the first pic below? See anything out of whack with the gun vise? Yep, the rifle won't fit into it.

A couple pics:

View attachment 7856375View attachment 7856376

you going to be able to shoot it, with the ejection port not lining up with the stock?
I like the color on your stock!!.
Looks like you just need to get some threaded rods, so you can extend the front of your rifle vise.

 

[Rocketmandb]

you going to be able to shoot it, with the ejection port not lining up with the stock?

It'll be tough... honestly, seeing this in person, it's very minor. I'll still probably alter it, but need to find a matching paint first.

I like the color on your stock!!.
Looks like you just need to get some threaded rods, so you can extend the front of your rifle vise.

It's a length thing. There are two stainless rods that go the length, and those need to be longer. I could also make an insert for where the rifle sits at the back end of this. Looking into it today.

 

[Rocketmandb]

@jasent What did you use for a bullet comparator on your 37XC? There's not enough room in the Hornady for the extra-long bullets.

EDIT: Just found that Sinclair has an XL size comparator body. Ordered it to see how it goes.

 

[babyguppy]

Rocket,
What bullet did you decide to go with?
I'm just curious to see how far off FPS of the 37XC is from the 375CT. I realize the 37XC should be a little lower. I'm just curious by how much. I've read a few things out on the net; would love to hear your actual numbers.
Thanks,
This is what GIXXER2000 was getting from his 375CT (pulled from a different thread)

I run a Cadex Shadow 375ct with a 35in Bartlein 1-7 twist barrel done by Robert Vestal. I shoot with the SWULR and in the last 5 matches I have 3 2nd's and 2 1st. The target are 1780/2205/2650/3085 and are 40x40 with 20x30 at 1780. Personal best 3 of 4 at 3080 and last match 8 of 8 2205. Longest hit 3895 took 4 shots for the first and hit 3 of 10​

Here is my load Data​

AVG FPS 3065 SD of 7.8​

400gr Cutting edge bullet​

Peterson Brass
215M Primer
N570 Powder 131.5gr​

 

[Rocketmandb]

Rocket,
What bullet did you decide to go with?

I've got a bunch of the Lehigh 353s and some of the Warners, so it won't be apples to apples. I've read that the 37XC comes in about 100-150 fps slower than the Cheytac.

 

[jasent]

With the Warner’s I just used oal. With the SMk’s I had no trouble Monos are typically so uniform that oal works well

Running the Seneca’s in my 300 wm I drilled my comparator a bit deeper.
Looking forward to seeing your results

 

[Rocketmandb]

First loads - hopefully heading to the range tomorrow to break her in.

 

[disky1]

First loads - hopefully heading to the range tomorrow to break her in.


View attachment 7860261

Ive been not so patiantly waiting to see what results you get. I just sold a rifle and am itching to build up one of these or the 375 enabelr. In canada.

 

[Rocketmandb]

Ive been not so patiantly waiting to see what results you get. I just sold a rifle and am itching to build up one of these or the 375 enabelr. In canada.

I'm forming and speeding up the barrel today and will be doing load development at a private range on Mother's Day. So, not much in the way of data available to you now, a little more next weekend.

EDIT: I'm forming with RL33 at somewhere in the neighborhood of a 5% reduced load.

 

[jasent]

How ya liking the T5

 

[Rocketmandb]

How ya liking the T5

All I can comment on are the looks

Will tell you more today.

 

[Rocketmandb]

Report from the range: holy shit!

Shot at 5:00 was the bore sight round. Next 3 were center. I adjusted left, then next 3 were on the left dot. Quite happy for this being a brand new barrel with a guess (low) for charge, and a guess at seating.

 

[Rocketmandb]

Also, RL 33 is slower in this than anticipated. I loaded up 116gr to be safe and low for forming and barrel break in, but it’s REALLY slow. Getting about 2750 at this weight and was expecting more like 2850. But since there is like zero info on this powder in this round, it was a guess, and I was aiming low for safety regardless.

My last 5 rounds increment up in 1 gr steps, but even the top one won’t get very far given where it’s at now. More to come.

 

[Rocketmandb]

And now my shoulder is feeling it …

 

[Rocketmandb]

122 gr of RL 33 got me up to 2922 fps. Still room to go, but not sure that I’m going to keep using it.

 

[babyguppy]

are you shooting the Warners in the pic?

• CALIBER: .375
• WEIGHT: 400gr
• G1 BC: 1.103
• G7 BC: 0.552
• MINIMUM TWIST: 9
• BASE TO OGIVE LENGTH: 0.650
• OVER ALL LENGTH: 2.350

 

[Rocketmandb]

are you shooting the Warners in the pic?

• CALIBER: .375
• WEIGHT: 400gr
• G1 BC: 1.103
• G7 BC: 0.552
• MINIMUM TWIST: 9
• BASE TO OGIVE LENGTH: 0.650
• OVER ALL LENGTH: 2.350

I’m shooting the Lehigh 353s here

EDIT: I have warners at home, but they are not the 400s.

 

[babyguppy]

@Rocketmandb
Wasn't sure if I should post here or in the 'what scope everyone is running in ELR'...

What scope is everyone running for elr

Currently run Steiner M7Xi 4-28 with MSR2 reticle, love it. I love mine out to max elevation, but then it's not a great holdover reticle. However, I just mounted it on an Era Tac, and now I can take it past my previous ~2100 yard max with my 300 PRC - so I'm set on that rifle for as far as it...

www.snipershide.com

but the question..
How are you liking the March? Now that you have time to put some rounds down your 37XC.. 1500 yards? 2,000? thoughts?

 

[Rocketmandb]

How are you liking the March? Now that you have time to put some rounds down your 37XC.. 1500 yards? 2,000? thoughts?

I am going to give you an answer that is, perhaps, as different an answer than you would expect... bear with me

I haven't had the chance to really stretch the rifle and scope out (1k) - and I haven't even really completed load development. This is due to the fact that I'm a founder in a startup trying to raise money in the worst environment to so in about 15 years. In short, I am dramatically distracted, stressed, etc.

When I get stressed, my mind churns. When my mind churns, I find it difficult to get to get to sleep. I am constantly thinking about matters of the day, and my brain just won't shut off. To try and get my brain activity toned down, I do breathing exercises, I take sleep aids, and I think about things that put my mind at ease.

Believe it or not, the thing that puts my mind most at ease is visualizing looking through my March scope. It is a very comfortable reticle to look through. The clarity is amazing. Also, not that it comes into my sleeping patterns, it tracks very well.