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Hi Guys

A few questions. What would be the ideal barrel length for a .338 for shooting long range , I'm guessing 32" ? My Aw currently has the factory 27" giving me about 2750fps with 85grns vit 165 . Would fitting a longer barrel give me faster speeds up to say 3000 fps or more but using less powder , basically increasing barrel/ brass life?

This is me just thinking ahead at the moment, the lure of long range beckons !ūüė¨

Gluv

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Factory 338 lap mag barrels are usually 27 inch.if you have a quick load you could find out how far up the barrel it's goes before the powder is all burnt.probaly not worth going any longer than that other than a bit more velocity

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When the military were testing the .338 Norma Mag (based off the same 416 rigby case, just a little shorter and practically is 80fps slower with both 250g and 300g projectiles) they found 26"-28" to be optimum. When Norma were testing, they used predominantly 26" tubes and noted that full burn was easily achieved before 26". Anything over 30" and you're gaining little velocity. 

Some chatter from chaps at Norma as well as Dave Tooley, who has a ton of experience with .338s and larger.

http://forum.snipershide.com/threads/338-norma-mag-barrel-length.51872/

Another source who cut down a .338 barrel is here:

https://rifleshooter.com/2017/03/338-lapua-magnum-barrel-length-versus-muzzle-velocity-30-17-inches/

 

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In reference to your load, I would say that 85gn of N165 is fairly anaemic. I assume you're shooting 250gn Scenars or lockbases? Really, you should be up around 2900fps fairly easily with the 250s. My Norma Mag runs the 300gn Scenars at 2780fps with Ramshot Mag. I'm keen to give RS80 a go, which should boost them to around 2830fps or so. 

If your AW uses a non CIP mag, you'll have to seat them fairly deep, thus reducing charge weight but increasing pressure. In addition, N165 has a relatively low energy rating too. Switching to something like RS80 / Reloader 33 or even possibly N170 will see your velocity increase 150fps or so - but possibly at the expense of some barrel life if shooting long strings.

If you do have the longer CIP mags and can seat longer (to lands) then you'll see even more velocity switching to a mildly higher energy powder (but be warned of the Vhit N560 and N570 powders...they burn Scorchio hot. There is the new N565 which may be suitable but I have zero experience with it).

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I did load test to about 2900 fps but was getting a rather stiff bolt lift so backed off. The load I'm at now proved the most accurate in testing .

I was kind of hoping for a bit of a free lunch with a future longer barrel ...As with most things , no free lunches ūüėŹ

Thanks for the replys, much appreciated 

 

Gluv

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1 hour ago, Gluv said:

I did load test to about 2900 fps but was getting a rather stiff bolt lift so backed off. The load I'm at now proved the most accurate in testing .

I was kind of hoping for a bit of a free lunch with a future longer barrel ...As with most things , no free lunches ūüėŹ

Thanks for the replys, much appreciated 

 

Gluv

Fair enough - I too prefer consistent accuracy over pure velocity. 

Even at 2750fps you should still remain supersonic out to around 1200-1250m. Mild load, mild(ish) recoil &¬†better barrel life.¬†Happy days! ūüėé

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It will be interesting to see what the barrel life runs to ūüôā

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14 hours ago, Catch-22 said:

Fair enough - I too prefer consistent accuracy over pure velocity. 

Even at 2750fps you should still remain supersonic out to around 1200-1250m. Mild load, mild(ish) recoil &¬†better barrel life.¬†Happy days! ūüėé

As a matter of interest, what sort of brass life are you getting at these higher pressures? I'm on my fifth reload at the moment. I anneal every time

 

Gluv

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I don't know yet...too early to tell. I'm using Norma brass for the .338 Norma Mag. I too anneal every time, so we shall see.

I think a big thing to note is that with RS powders, I've found they operate at a lower pressure whilst delivering a higher velocity. I have found with Vhit N140 in my 6.5x47 barrel, I can get good velocity but it is at the top end of pressure. Many here on the forum who are using RS52 in the same cartridge experience higher velocity than me, but for lower pressure. 

What would be interesting is to see whether barrel life is more detrementally affected by heat of explosion (so the Joules of energy imparted by the powders ignition) or the amount of pressure developed. One would naturally assume it's both, but I wonder if one is worse for barrels than the other. If, hypothetically, pressure was worse than just heat, the RS powders (which seem to produce lower pressure) could be the key...despite their higher energy ratings than say a cooler burning powder (e.g. I'm thinking RS80 compared to Vhit 165).

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4 minutes ago, Catch-22 said:

I don't know yet...too early to tell. I'm using Norma brass for the .338 Norma Mag. I too anneal every time, so we shall see.

I think a big thing to note is that with RS powders, I've found they operate at a lower pressure whilst delivering a higher velocity. I have found with Vhit N140 in my 6.5x47 barrel, I can get good velocity but it is at the top end of pressure. Many here on the forum who are using RS52 in the same cartridge experience higher velocity than me, but for lower pressure. 

What would be interesting is to see whether barrel life is more detrementally affected by heat of explosion (so the Joules of energy imparted by the powders ignition) or the amount of pressure developed. One would naturally assume it's both, but I wonder if one is worse for barrels than the other. If, hypothetically, pressure was worse than just heat, the RS powders (which seem to produce lower pressure) could be the key...despite their higher energy ratings than say a cooler burning powder (e.g. I'm thinking RS80 compared to Vhit 165).

That's very interesting! I may have to look more closely into this

Gluv

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You wont achieve the cartridges true potential in the AW platform, so 26" is fine.

A single shot rigid action with a 32" inch barrel , and a chamber tailored to allow correct seating of the 300gn OTM Berger will get to 3000Fps and is a very potent platform.

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And it was this exact thinking that led me to the .338 Norma Mag. It was designed specifically around the long 300gn SMK, seat the boat tail junction to the optimum neck/shoulder all whilst allowing you to seat within AICS mags. 

I have heard of US shooters pushing the 300gn bullets in the 338 Norma to up around 2900+ (as the Norma is about 80 to 100fps slower than the Lapua when its bullets are out of the powder column). BUT I think that's pushing things too far - too far for me anyway. Barrels will be toast fairly quickly due to the use of the very high energy Vhit powders. 

My ballistic solvers tell me that launching a 300gn Scenar at 2770-2800fps will reach the transonic zone at around 1550m. 

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I'm using 300gr Matckings and 91 gr of N570  I get about 2730 which brings me in just under 5,000 ft lbs which is my local 100 yard range energy limit.  it means I can load develop quite easily.  also 91 gr proved to be a fairly accurate round.  also with this load I am supersonic (at normal UK temps and pressures) out to 1500 yards.  my barrel is 26" and 1:10 

 

Andy

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I'm with Paddy on this.

You have to remember that rifles such as the AW and other military role .338's were not designed as an out and out velocity horse. The weapon has to be portable, and able to be used in confined space [of sorts ] Thats the main reason for the 338 and also the .50 barrel lengths.

I've yet to try it in my own AW338, but i picked up a couple of tubs of the new vhit 565 powder. It was designed specifically for the .338.

Got to be worth a try, as I usually run 165 with a 250 grain scenar in my own.

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2 hours ago, baldie said:

I'm with Paddy on this.

You have to remember that rifles such as the AW and other military role .338's were not designed as an out and out velocity horse. The weapon has to be portable, and able to be used in confined space [of sorts ] Thats the main reason for the 338 and also the .50 barrel lengths.

I've yet to try it in my own AW338, but i picked up a couple of tubs of the new vhit 565 powder. It was designed specifically for the .338.

Got to be worth a try, as I usually run 165 with a 250 grain scenar in my own.

Thanks for posting this Dave, I wasn't aware of 565 ūüė≥ I shall have to try a tub myself¬†

Gluv

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On 7/17/2018 at 6:54 PM, Catch-22 said:

When the military were testing the .338 Norma Mag (based off the same 416 rigby case, just a little shorter and practically is 80fps slower with both 250g and 300g projectiles) they found 26"-28" to be optimum. When Norma were testing, they used predominantly 26" tubes and noted that full burn was easily achieved before 26". Anything over 30" and you're gaining little velocity. 

Some chatter from chaps at Norma as well as Dave Tooley, who has a ton of experience with .338s and larger.

http://forum.snipershide.com/threads/338-norma-mag-barrel-length.51872/

Another source who cut down a .338 barrel is here:

https://rifleshooter.com/2017/03/338-lapua-magnum-barrel-length-versus-muzzle-velocity-30-17-inches/

 

I see what you are saying and why but I don't think I would be betting my house on it.

The chatter is exactly that, chatter; and the study does not look statistically valid. To be fair to the guys that did it, they actually say that themselves in their comments about sample size.

Looking at the standard deviations and the changes in velocity, they are so similar at the longer barrel lengths that you could prove anything you wanted. Some of the numbers also just look odd which demonstrates the problem. As the numbers don't go beyond 30" and are dubious close to that value, I don't see how anyone can make any informed comment at all never mind a definitive statement.

Still it is better than nothing? Maybe not.

The other point in the thread in general I don't really get is the apparent belief that once the powder is burnt then any extra barrel is a waste. Well if the bullet still had 30 kpsi or whatever up its chuff it is still going to accelerate so the extra inches are worth while ? I have not run quickload on this cartridge but on others that I have the powder burn often finishes well down the barrel and the residual pressure adds a lot to the final muzzle velocity

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Chanonry - I completely agree with you. It would always be great to have as wide a sample size as possible to ensure the data is as rock solid as possible. I guess in the absence of such testing conducted by anyone with vast data on which we can base concrete findings (as far as I'm aware), I'm simply going on what I've come across when asking the same question as the OP myself.

I guess that's all we can do, rest on the shoulders of people (with vast professional industry experience - even though it may sometimes come across as informal 'chatter') who have taken the time and expense to conduct the experiments we haven't or can't and interpret their findings to apply to our own thinking and testing.

As we're all here to learn something new, i'd welcome any concrete data or experience from learned industry experts who categorically recommend using 32"+ barrels in .338cal over the 26"-28" flavour and whether doing so makes such a significant gain that it outweighs the cost and effort to do so.

I'd happily go with a longer barrel myself if the gains were significant, but I've not read anything to suggest it is. If anything, everything I've read suggests that longer barrels are less ridgid and will if anything aid the 'whipping' effect when fired. Shorter, fatter barrels are more rigid which aid accuracy. But again, that's based on what I've read - I'm no industry expert and I'm completely open to being corrected. 

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I’m running a Surgeon XL, with 250g I achieve 2980 FPS with 91 g RL 25 

Accuracy is very good from the 28‚ÄĚ PAC Nor barrel¬†

300 grainers are slightly slower but accuracy equal to the 250’s

 

Havent  tried RS powders yet 

 

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On 7/20/2018 at 6:59 PM, baldie said:

I'm with Paddy on this.

You have to remember that rifles such as the AW and other military role .338's were not designed as an out and out velocity horse. The weapon has to be portable, and able to be used in confined space [of sorts ] Thats the main reason for the 338 and also the .50 barrel lengths.

I've yet to try it in my own AW338, but i picked up a couple of tubs of the new vhit 565 powder. It was designed specifically for the .338.

Got to be worth a try, as I usually run 165 with a 250 grain scenar in my own.

Just out of interest where did you get the V565 from - I can't seem to find any available in on-line listings?  Thanks

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Any vhit stockist, or from Hannams at Leeds.

 

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Hmm OK I'll try Hannams as a lot of folks aren't listing it.

Has the data been released for quickload yet - to model it to see if there's any mileage in working up a load?

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No idea, I don't use it.

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N565 is in the latest QL update.

For want of a better term it appears to be cooler in combustion with reduced pressure.  In very simplistic terms n560 still gives the raw velocity edge when modelled.

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