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338 Allen vs. 338 Snipe tac vs. 338 XT - Which one?

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Old 08-03-2009, 11:07 PM
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Re: 338 Allen vs. 338 Snipe tac vs. 338 XT - Which one?

THe original question for this post was about the ultimate in 338 performance chamberings, not about the most efficent so that is why no other chamberings are rally being mentioned to the poster, that question was just not asked.

No doubt your wildcat would be efficent and I am sure its in the same class of the 338 Win Mag and 340 Wby, should be exactly right between these to to be honest.

Again, the reason for not mentioning the smaller 338 chamberings was not because nobody feels they are capable rounds, but simply because they were not asked about.

The interest was about the top rung of 338 performance, that is what the topic has stayed on track with. Your wildcat sounds like a neat round, just not pertaining to the topic at hand is all.

By the way, what velocity are you getting with the 250 and 300 gr bullet weights in your 338-300 Win Mag?
Kirby Allen(50)

Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

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Old 08-04-2009, 12:04 AM
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Re: 338 Allen vs. 338 Snipe tac vs. 338 XT - Which one?

Hi Kirby,

I did try to put in a disclaimer:
"I realize they are far from biggest/baddest and were no where near 1mi capable rifles....
Just posting this to mention the other side of the equation.."

As far as velocity, don't own a chronograph so not really too sure. I extrapolated my data from the .330 and 300 Dakota ctgs which have same capacity and the .340 and .300 Weatherby ctgs which are identical in dimension except for neck diameter. I expect that the 250gr bullets provide about 2800fps with the max load I worked up. Have lots of XMR4350 and am happy with the power band in this cartridge.

Have not tried any 300gr bullets yet. Haven't even really kept up with cutting edge bullet development in the .338. Been pretty hard to get bullets anywhere. Probably will order some Matchkings to try out first.

In theory, the .338/300 should, if given enough elevation adjustment, be able to acquit itself pretty well at extreme distance shooting a high BC bullet. Maybe my 1:10 3groove pac-nor is a tad too slow? Seems most are going 1:9.4 these days...

I ordered the barrel on a pre-fit basis from Pac-Nor chambered for the .338Win with them knowing I would improve the barrel to .338/300. I chambered the barrel to a minimum oal dimension which is what i have seen provides best accuracy and assures headspacing on shoulder rather than belt. Since there's no SAAMI chamber dimension for .338/300 I use virgin .300mag Win cases and an RCBS Precision Mic. I chamber so the case expands about .005 over the average measurement I get in the Mic for virgin cases.

Not a blistering flat-shooting Big Honcho of a round, but one that is very versatile. Something I found the big guy ctgs weren't.
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Old 08-04-2009, 01:21 AM
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Re: 338 Allen vs. 338 Snipe tac vs. 338 XT - Which one?


Just for your information seeing as you have no chronograph. I get 2735 fps with 250 grain Hornady BTHP Match bullets, from my Sako 338 Win Mag and 25 inch barrel. 70 grains AR2209 powder.

So if you are only going to get 2800 fps from that wildcat, then its not much of an improvement? If I had 26 inch of barrel like yours, I would be even closer.

With regards to the big 338's I would be interested to know which one was easiest to get cases for? I would realy love one but down this way, these sort of cartridges cases would be as rare as rocking horse ****.
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Old 08-04-2009, 02:44 AM
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Re: 338 Allen vs. 338 Snipe tac vs. 338 XT - Which one?

Velocity is not the end-all solution for longrange shooting. Case in point, the .338Whisper is pretty well regarded for accuracy and ability to deliver a heavy high BC bullet. Kinda like the .338/300 for its ability to cover a wider spectrum of load potential than other rounds that are magnums. I do have some other slow-burning powders that might raise the velocity, but why?

I've found that medium velocity loads tend to be more conducive to accuracy Talk to the techs at Sierra about how promptly max-load magnums burn up their barrels. Then consider the chamber dynamics and minimum oal as discussed. A benchrest smith might set a 6mmPPC chamber to be .0005" longer than SAAMI specifications. Not talking about neck-turning tight chambers.

3400fps with a 300gr bullet is damned awesome but, how much difference does it make out past 1000yds compared to the same bullet started at 700fps slower? (Not saying I can generate 2700fps w/300gr bullet, but if both are zeroed at 300yds the 3400fps bullet has lost 300fps of its initial advantage over the 2700fps round. Sure trajectory is more rainbowlike, but 18moa versus 30moa is not a big deal.

At 2000yds, I don't know... What I do know is flat shooting is out the window for either round and it all comes down to scope come-ups at that distance. That plus chamber dynamics and inherent accuracy.

The .338/300 is only about 100fps shy of the .338rum, but can be moderately loaded, which rum and full-sized H&H cases like the Weatherby cannot. In the .338/300 you gain 5 grains of capacity over the .338win, and have (in the Sako M995 action) a gain of almost half an inch of magazine space in which to seat your bullet. ETA: compared to the .340wby which is .205 longer than the .300win case.

Maybe the Chey-Tac sized actions have over 1.25" of room to work with when seating bullets, but no others have as much as the Sako M995, (3.75" inside magazine oal) I am pretty sure.

If you are chasing the velocity demon, there are other powders. I see a lot of endorsements for H4350 in the 6mmXC. I have a 6mm/.22-250AI which is about the same thing, but for AR-10. I might try XMR4350 in that match upper since it has an extra length gas tube and XMR is definitely the mildest of the 4350 burn rate powders.

A better fill-rate producing a bit less in pressure & velocity will likely be more conducive to accuracy.

With a hellacious powerful scope and 100 moa of elevation, maybe at 2000yds the .338/300 could compete? If a .338Whisper can deliver contending accuracy at 400-500yds, aside from some need to own The Hammer of Thor what serves you better? The target at 2000yds can't distinguish from a 1000fps delivery or an 1100fps delivery.

ETA: Topshot; I didn't even think about velocity gains due to barrel length. The numbers I cited were just extrapolations from Barnes and Nosler manuals, plus the Accurate Arms loading manual. I will also state that I am growing of the opinion that longer barrels are not intrinsic aids to accuracy. 22" may actually be about the optimum length for barrel harmonics, otherwise why is 20-22" so popular with benchresters? Terrain in my area is dense sub-arctic almost jungle, and I carry and still hunt with my rifles. Maybe a 24" is optimum for a sub H&H case like mine, I don't know. Just know 26" balances pretty decent, but shorter barrel would carry more easily on a sling.

Last edited by edward hogan; 08-04-2009 at 03:11 AM.
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Old 08-04-2009, 03:45 AM
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Re: 338 Allen vs. 338 Snipe tac vs. 338 XT - Which one?

I think you are wandering off the subject of the thread a little. I would like to hear about the BIG Bangers and what I need to get one.

As your 338/300 would be in the transonic range from about 1200 yards onwards, I doubt it would get anywhere near 2000 yards with any sort of accuracy. This is what the Big Bangers are designed to do.

Also I think there is a bit more to it than applying at bit more dial up! What about a little thing called wind drift. As your time of flight would be a lot longer, your wind drift would be much greater.
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Old 08-04-2009, 01:23 PM
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Re: 338 Allen vs. 338 Snipe tac vs. 338 XT - Which one?

Not my intent to give offense.

Good luck with your information gleaning.
Best of luck with any super longrange rifle project you may decide to pursue.

Your remark: "As your 338/300 would be in the transonic range from about 1200 yards onwards, I doubt it would get anywhere near 2000 yards with any sort of accuracy", shows me you have lots of ballistics theory to digest.

I was able to find my Sierra 50th anny manual a moment ago.
Started at 3400 fps the 338 300gr smk has lost 1200 fps at 1000yds, and is going at 2196 fps.
Started at 2700 fps same bullet has lost 1050 fps, and is going 1656 fps.

The same bullet with MV of 1900 fps is still at 1137 fps at 1000yds.

If the physics of the ballistics is relative, then a bullet already going 1656 fps will drop off another 700 fps in the next 1000 yds. (Probably won't have as much a decline, but not having a ballistics software program, I am swagging.)

At any rate, looks to me that any cartridge that starts a 300gr .338 smk at 2700 fps is still super-sonic at a mile easily.

Not to be heretical, but... if a milder load in a shorter barrel provides better intrinsic accuracy with the same bullet it is more likely to do so at distance as well, and it is way more useful in a greater variety of situations.
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Old 08-04-2009, 01:28 PM
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Re: 338 Allen vs. 338 Snipe tac vs. 338 XT - Which one?

Edward, the biggest gain the big boomers have over the 'regular sized' boomers , isn't less drop.
1) Less windage (and thus less error in judging the wind)
2) Ability to get good terminal performance at further distance.

If some is good and more is better, then too much is just right.

My mind is a raging torrent, flooded with rivulets of thought, cascading into a waterfall of creative alternatives
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