300 wm Build Questions

Clarktar

WKR
Joined
Aug 30, 2013
Messages
4,174
Location
AK
I am starting to plan a 300 win mag build and was looking for some input. I would like the rifle to around 7 to 8 lbs when done (8 lbs with scope would be great).

I am curious about barrels. I have read about twist rates anywhere from 1:8 to 1:10. Seems like 1:9 is now recommended over 1:10, even though 1:10 was the standard for a very long time. Anyone use both 1:9 and 1:10 and have any input on the twist rate to choose?

Bullets: I am well aware of the 215 load and success many have had with it. But I was wondering if the 300 wm could shoot a 230 as well (shoot it well). Is there a twist rate that would be better for a 230 gr?

Does anyone have any specs (weight) on a "lightweight" barrel suitable for the 300 wm?

Last question for now, has anyone on here had experience with trigger tech triggers?

Thanks,
 
Joined
Dec 30, 2014
Messages
8,170
People have shot the 230s and 215s successfully for some time with 10 twist. You might lose a small incremental BC value from not being as stable at low altitudes but it hasn't seemed to be a problem. I think the other thought is a faster twist would transition better into transonic speeds, I don't shoot that far and can't comment with experience. I think people have found better ballistics with the 215s at 2950 vs 230s at upper 2700's FPS. The 215s have a better form factor than the 230s, so you don't get a ton going from 0.69X G1 to .717. That said, if you planned on getting more close shots the slower speeds of 230s might perform a bit better. I wouldn't rule out the 208 or 225 ELD-m.

I shoot a 300 NM with a Hawk Hill 9 twist tube that has only seen 230s, it has been very accurate and not very sensitive to loads but it is a Medium Palma contour barrel as well. I saw recently that benchmark barrels had recommended to someone to go with 9.5 twist as they were seeing a little more finicky load development with some 9 twist barrels.

I've been long considering a lighter 300 mag. I'll probably burn some cabelas bucks on a Seekins Havak once they release the specs for 300 WM (the ones on cabelas aren't accurate). They'll have at least a 10 twist and come with a carbon fiber 3 round magazine that doesn't protrude like the pictures show and allow for nearly 4" COAL. Can't build that rifle for close to that $.

Seekins Precision Havak Centerfire Rifles : Cabela's
Seekins Precision Havak Bolt-Action Rifle : Cabela's
 

odin0226

Lil-Rokslider
Joined
Nov 20, 2015
Messages
109
I would lean towards the 215 in a 300 WM, due to MV. You aren't gaining anything with the 230 until your shooting beyond 1400.

I can say this first hand: 215's ive never lost an animal, 230's ive never recovered one.
 

Wapiti1

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Joined
Sep 18, 2017
Messages
3,569
Location
Indiana
If you are building, go 1:9 and then you don't have to think about it anymore. 1:10 is fine too, but since you can choose, there is no downside to a faster twist IMO. I shoot an X-caliber barrel in 1:9 on my .300 Win and it is a very forgiving barrel with bullets from 180 up to 215.

As noted above, the .300 Win really needs an extra long mag box to utilize the 230gr bullets. Even the 210's benefit from that longer box.

Jeremy
 

2five7

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Joined
Jul 15, 2017
Messages
657
8 lbs scoped is quite light for a 300. You're talking 6lb rifle, and you'll want at least a 26" barrel if you're planning on getting the most out if the heavy bullets. You'd probably need a titanium action and either a carbon barrel or very light contour steel.

A good long range optic, with a 20 moa base and rings will weigh at least 2 lbs, if not more.

Can be done, but going to be pricey.
 

mtnwrunner

Super Moderator
Staff member
Joined
Oct 2, 2012
Messages
3,886
Location
Lowman, Idaho
I am starting to plan a 300 win mag build and was looking for some input. I would like the rifle to around 7 to 8 lbs when done (8 lbs with scope would be great).

I am curious about barrels. I have read about twist rates anywhere from 1:8 to 1:10. Seems like 1:9 is now recommended over 1:10, even though 1:10 was the standard for a very long time. Anyone use both 1:9 and 1:10 and have any input on the twist rate to choose?

Bullets: I am well aware of the 215 load and success many have had with it. But I was wondering if the 300 wm could shoot a 230 as well (shoot it well). Is there a twist rate that would be better for a 230 gr?

Does anyone have any specs (weight) on a "lightweight" barrel suitable for the 300 wm?

Last question for now, has anyone on here had experience with trigger tech triggers?

Thanks,

Hey Chris, how far do you reasonably want to shoot it?

Randy
 

Fitzwho

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Joined
Apr 18, 2017
Messages
956
Location
Midland, TX
I would look at a carbon barrel, I built my 300WM with a Carbon Six (and had them do the gunsmith work). I went full bull barrel (23”) and kept the rifle right at 9lbs with a 3-18 VX6 on it. You could shave weight by going with a lighter contour and a titanium action and probably have it come in around 8lbs scoped if you have those kinds of funds.

I’m running 200 ELD-X at around 2800-2850fps, can’t remember exactly since i’ve been messing with my Creedmoor since October. With the HS Precision detachable Mag I can load the 200’s out to the lands without issue (interestingly cannot do that in the short action).
 

mtluckydan

Lil-Rokslider
Joined
Dec 7, 2012
Messages
286
Or you could buy a Cooper and be done with it and be in the 7-8 pound range even with a heavy optic & 1/2 moa guarantee

Sent from my P00I using Tapatalk
 

2five7

WKR
Joined
Jul 15, 2017
Messages
657
Or you could buy a Cooper and be done with it and be in the 7-8 pound range even with a heavy optic & 1/2 moa guarantee

Sent from my P00I using Tapatalk

Looks like the Backcountry model would fit the bill for him, under 6lbs bare.
 

JigStick

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Joined
Aug 26, 2016
Messages
337
Location
Pittsburgh
What game do you plan on hunting, and at what ranges? Ive built a few 300mags.

If you are shooting anything from elk size and down, at ranges under 1000yds you can shave some weight and not lose any performance by going with a 300WSM. Using a Stiller Predator medium action will give you all the throat and magbox length you need to seat bullets far out. Go with a #3 barrel contour and a McMillan ultralite stock, talley rings, jewell trigger, and BDL of your choice and you should easily make weight.

We use this combination a lot here in western PA. Some with barrel twist rates as slow as 1:13, pushing 140g Triple Shocks at 3500fps. Absolutely crushing white tail and black bear. If you want to shoot some the 160-180g bullets you could get away with a 1:12 or 1:10 twist and really deliver some heavy energy down range.

When trying to make weight every oz counts. And using a medium action instead of a long action will save some. And using sporter barrels and keeping your tang length to 1.5in or less will also make up some savings.
 
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