338BR/338 Whisper noob questions
 

Guys, I'm considering a build in .338W (338/7BR). I'm so new to this idea that I don't even know what to ask.

Here's what I'm looking for out of it: Longer range accuracy (500-600 yards minimum ideally- never opposed to reaching farther though), primarily subsonic suppressed shooting, and planning on using 300gr SMK's. I've combed these forums using every name I can think of for the cartridge, and really can't find very much info. I've read every thread I did find hoping to avoid being the noob that asks the same thing that's been asked and answered a million times already, but still haven't gotten what I'm looking for so here goes...

My primary reasons for choosing the 338W is 1) I already have a stripped 700 action with a .308 face waiting for a purpose in life. 2) Acoording to Cartridges of the World this seems to be suitable for my range/accuracy aspirations.

I'm thinking the bbl length should be somewhere in the 12"-16" range (I understand the SBR issues), and around a 1:7 twist.

I guess my two biggest questions are: Is this a suitable cartridge for the ranges I'd like to reach, or is something better suited for this (ie. 510W)? Am I in the ballpark on the bbl length and twist?

Any input is appreciated, just trying to use the action I have if possible. Thanks for any help you can provide.

First I would much rather sell you one of my 338 THUMPERS since it is the best cartridge that will ever be designed.:grin: But I do understand wanting to use the action you have. You never said what you are going to be using it for which can effect if it is suited for what you are doing with it. I would shoot a hog at 500 yards with our 50 THUMPER but until I do some more testing I don't think I would shoot one with our 338 THUMPER at this point, but the 338 is great fun to shoot steel targets at 500 yards.

In researching subsonic rifle cartridges I found that they all have close to the same drop which at 500 yards is about 23 feet. The limiting factor with subsonic cartridges is the amount of drop and not the range they can shoot accurately.

You are correct in barrel length, I would suggest to not go shorter than 10" for what you are doing and 14"-16" would probably be ideal. I use a 8" twist on my 338 THUMPER and have not had any problems with stabilizing anything.

As far as subsonics being a good choice for that you want to use it for its kind of up to you. If you can deel with the drop you should be fine.

Despite thread jumpers trying to sell you stuff other than what you are asking about, the 338BR is a great cartridge and quite versatile. It will do what you want. As richard noted any .338 will have about the same ballistics if you're starting at the same speed. The advantage to the 338 BR is that it will fit your bolt face unmodified and is already pretty well tried and true. The .338 bullet has great ballistics and if you've got a scope with enough elevation adjustment you can get out there to 1000yds. There is also enough room in the BR case to load supersonic which gives you more possibilities. Thats a big advantage over other subsonic 338's. Depending on exactly what you want other cartridges might be just as good. The 510 is really neat but brass is expensive and harder to make. Its also a pretty large and long cartridge so mods would have to be made on the bolt and receiver to make your current rifle action work. It does do the job though and has the advantage of being able to find "fun" bullets like tracers, API and APIT and even spotter tracers though they require a special throating reamer be used. So the basic question is what do you want and what rifle are you starting with. From what you've posted the .338BR is an excellent choice.

Hope that helps and if I feel the need to sell you something I'll post it on the for sale boards where those posts belong.

Frank

I have to appologies for my earlier post. I ment the first line as a joke. I was not trying to sell you something you didn't want. I refer to my THUMPERS as I have more experience with them then other subsonic rifle cartridges.

Frank brings up a good point in regards to case capacity. You will be able to get good supersonic velocities with the 338 BR. With our 338 THUMPER we get about 2100 FPS before we run out of case capacity and the 338BR has a much bigger case volume.

Mr. Hoffman, whats the heaviest bullet you've stabilized with the 8 twist and have you fired anything lathe turned or cast?

I have shot the 300GR Sierra Match Kings and the 300 GR. Woodleigh RN which have both stabilized fine and shot well. I just cast up some 220 gr from a Lee mold but I have not shot them yet. If anyone known of some heavier bullets they want me to try I'm game.

Spook,

What is the heaviest 338 bullets you have found. I have only foung 300 GR and 220gr molds for the cast. If you wanted some cast bullets let me know. They are not sized but they are cast up if you want somt to try.

Glad to hear I'm not completely off base so far. amafrank, what are your thoughts in regards to barrel length and twist rate for the 338BR?

The project just moved ahead a step, the research continues...:smile:
Thanks guys.

300SMK, 300 Lapua so far,260 Glenhill cast on hand in quantity but thanks. All three went very sub MOA in the rifles I've built. I am surprised that an 8 twist stabilizes the 300's @ your elevation (atmospheric density) as both JDJ and the Engineers at Berger told me to use at least 7.

I've been going with a 6.5 twist x 16.5 barrel in anticipation of shooting Lehighs lathe turned 338 and Hornady is about to give 338 shooters a nice surprise from what I'm told.
The lathe turned bullets make the subsonics really shine over distance if my other rifles are any indication.

Mad Rabbit it seems your thread is getting hijacked, sorry.
Where in CO are you?

I think that anything over 16" doesn't really gain you anything other than a little safety in legal barrel length. Anything under means you have to register it as a short barreled rifle. So my opinion is 16" maybe + a quarter inch to be on the good side. As far as twist rate I've been looking at 1:7 or 1:8. The larger diameter of the .338 over the .30 cal will give it more gyroscopic stablity at the same rpm relative to the .30 cal but on the other hand those 300gr SMK's are mighty long. I think I'd have to say listen to Spook on this one as he's actually been doing some shooting and I'm still working on collecting parts to put one of these together. Its not always possible to simply compare other cals to come up with twist rates. Over spinning is less likely to give you problems as compared to underspinning too. I'd hate to knock the baffles out of a can if I wasn't a class 2 manufacturer. I hate to knock them out even being a class 2....
One piece of advice is to buy a good quality blank to have your barrel made. Its worth the cost to have a component you know is correct so you aren't chasing a number of unknown variables with a new rifle and cal.
Hope that helps

Spook,
I'd have to say that the heaviest .338's I've seen are the 300's too. The SMK's and some other round nose designs. . . I've been looking at having a mold made up for both the .338 and the .510 but not sure what design I want or weight. We've been shooting the 510 more but all the .338's have been in the Lapua.

Frank