Twist Rate Required for 300gr MK Bulet


Well-Known Member
Jun 8, 2001
Calgary, Alberta, Canada
Does anyone know the twist rate required to stabilize the .338 Sierra 300gr MK bullet?

I have access to a .338 Win Mag and would like to try some long-range hunting on game bigger than coyotes and gophers.

The rifle in question is a Rem 700 with a factory barrel of undetermined twist rate.

I looked up a twist rate chart and it only showed one twist rate for the .338 calibre. It listed 1:10 as good for "all bullets". Does this really include the big 300gr version?

Peter Cronhelm

All the 338's I've had were 1x10. I shot the 300MK out of two of them and had good results.
Hi cronhelm,

last year i´ve visited a 1000 Meter prone Match in swizerland. One of the Guy´s there shot a .338" Lapua using the 300grs SMK`s from a french sniper - rifle. He finished with a 289 of a possible 300 score....
He told that the Barrel had a 1x10 Twist....


Yes you've got a good safety margin with the 10" twist even with the lower velocities of the 338 Win Mag. A 11" will work and I know of 1 fella using a 12" but Dan Lilja has told me that a 12" won't work. According to my caluclations a 12" is right on the line of an not-so-exact science so I'll take the word of experience here.

every 338 used in BR competition that I know of right now including my own is using a 10" twist with the 300 Sierra's. All of my impacts are cutting very good holes without hardly any measureable yaw in the paper.

The only other thing I would add though is if your using a factory 338 Win Mag that is throated short for the standard weight 338 bullets is to watcch your pressurue signs. The 300gr bullet is long and will hog up a lot of boiler room capacity raising pressure very early.

Good luck though. I've heard that this combination works really well for accuracy.


At Hawks Ridge last year, I had several long chats with Rich (surname started with M but I forget it), one of the senior support guys from Sierra. I was talking to him about a 338 Lapua Improved rifle I am building and he told me to get a 1/10” twist, then I could shoot the Sierra 300gn bullet, plus the new 250gn 338 bullet Sierra had coming out. Also, Lapua make a 250gn 338 match bullet which I am pretty sure is available from Sinclair.

I think for really long range shooting, the 300gn bullet would be the go, but you just never know what an individual barrel will like.


Thanks for all the info. I called up Remington (this is a factory barrel) and actually got an answer in a minute or two. The rifle is indeed a 1:10 twist so it should work fine.

Now does anyone know of a CDN source for these bullets? The US exchange rate is a killer!

As far as the throat goes, I have never seen a chamber with a really short throat yet. As I understand it the big bullets like to be seated into the lands somewhat so I shouldn't have any serious problems with reduced case volume due to the size of the bullet.

On another subject, I did some research today and "discovered" the .338 Rem Ultra Mag. What say you about this cartridge? I looks llike it could have some potential as a long-range cartridge due to the lack of a belt and about 200+ fps more muzzle velocity than the .338 Win mag. The cartridge is also available as a factory chambering which means it does not require a very expensive custom rifle and wildcat cases.

The Rem 700 Sendero in .338 Ultra Mag might just be the poor man's long-range hunter.

Peter Cronhelm

PS I am starting to feel bad cause I have been bitching for months about all the hunter's out there with Magnum Itus and now here I am talking about using big magnums.
The mans name from Sierra is Rich Machholz.

The 338 UM isn't a bad choice for a sporter weigh rifle for long range shooting. The case has the capacity and the Sendero type rifles (aluminum bedding block and HS stock) with a 26" barrel have a good reputation for accuracy. And that 26" barrel will help, though it would be nice to have a couple extra inches hanging out there IMO. But for a poor mans LR rifle I say you could do much worse!
Recoil will be rather stiff wiothout a brake on it, and much tougher to spot your own impacts also. just a suggestion for your consideration.

Also in reference to my comments above about the bullets hogging up case capacity. I see your comments on never seeing a short throat. If you've never seen or loaded these 300gr bullets you'll know what I talking about when you see them. These bullets are as long as a 223 Rem case to give you a comparison. I've never seen a factory throat long enough to seat these bullet into the lands and not have the bullet sticking way down in the case. Remember factory gun throats are cut for the max. length of the magazines not the longest bullets made for that caliber. Not arguing only raising the safety flag and saying just be careful when loading and have fun!

Your bit and on your way....... have fun with your magnum! with or without the "itus" to go with it. Who cares? shooting is shooting period.

Good luck!
I owe you something and your emails are getting rejected. Can you email me please if your account has changed or something. If not I'll keep trying.

sorry for the off topic post folks.

I took a more in depth look at the ballistics involved and here are my thoughts.

The .338 Win mag, not being a HUGE case may not be the best vehicle for launching the big 300gr Sierra's. Lapua sells a 250gr bullet with a BC of .675. The lighter bullet will give me more case capacity as well as being easier to drive to faster velocities. This should translate into a loss of downrange energy but a gain in downrange velocity and a flatter trajectory. At 1900yds the 250gr bullet would still strike with more than 600 ft/lbs of energy.

The Lapua bullets also have an excellent reputation for accuracy.

Another conversation on this board brought up the fact that loads of deer are killed with .357 Mag revolvers which have a **** sight less impact energy than a 250gr .338 bullet.

The only downside to the Lapua bullets is they only come in boxes of 100 and they are a bit more expensive than the Sierra's. So if I decide to go this route I have at least 100 punishing shots to make out of an unbraked, lightweight .338 Win Mag. My shoulder hurts just thinking about it.

Peter Cronhelm

Sierra now has a 250 .338" Match King. The BC is
.587 @ 2150+
.606 @ 2150-1700
.576 @ 1700-1400
.484 @ <1400
Load from a Disk says that in a 26" tube pushing the 300gr MK in a 338win the MV will be in the 23-2500 fps range. The 250 will be in the 25-2600 fps range.
If the Lapua 250gr got your attention on price, have you looked at the 300s? Sierra only sells them bulk in boxes of 500. The cheapest I've ever seen them is for approx $180 bucks. that is expensive in US dollars let alone the exchange rate for Canada.

But as pointed out above Sierra also makes a 250gr MK as of this Jan/Feb time frame. If you use the Lapua bullets they tend to run a little bigger at the pressure ring so you'll get more pressure with them then other bullet brands.

Good Luck!
I have seen listings for the 300gr Sierra in boxes of 50 from two separate sources.

I noticed the remarks about these being specialty bullet in the 500 ct pack.

So which is it does Sierra sell these things in 500's only or in 50's as well?

Does anyone know for sure?

If it is the 500 pack then that makes the Lapua choice even easier.

Peter Cronhelm
D&R Sports sells both the 250 and 300 grain Match King 50/box. The 300s are listed at $19 50/box and $160.92 500/box and the 250s for $16.76 50/box $152.41 500/box.

[ 07-21-2001: Message edited by: txhunter ]
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