Reloder 17 with 175 HPBTs in 308 win?

[mao0720]

Will this workout ok from a 24in Barrel or is RL 17 too slow? I recently picked up 400 175gr HPBT and I have several lbs of RL17 leftover from loading for a 260 rem I no longer have. Does anyone have a good starting point for powder charge weight?

 

[Laurie]

Re17 is too slow burning IMO. I tried it with the 185 Berger Juggernaut, 200 SMK, 208 A-Max and 210gn Bergers. It only performed with the 208 and 210s in my rifle. MV was good with the 185 and 200, but velocity spreads and groups weren't. That was in a 30-inch barrel, so plenty of space for a near full charge burn.

 

[savageshooter86]

I have always seen/read RL 17 for heavy bullets. For the good ol 175s may want use RL15 or get heavier bullets.

 

[mao0720]

This is all kind of what I figured. I need to find something to do with all 4 lb of RL17 that I have. Its not in the original containers so I cant resell it. Maybe Ill write my name in the front lawn.

 

[savageshooter86]

save it and if you ever shoot heavies.

 

[mao0720]

Thats my actual plan.

 

[amlevin]

I tried some with 175 gr and wasn't real impressed. That said I used some more with a batch of Berger 185 gr Juggernauts and got a couple of cloverleaf groups at 300 yards with reasonable speed.

Now if I could only find more of both, bullets and the powder.

 

[gsg5pk]

Based on their burning rate, I would keep those RL-17 for heavier projectiles like 185 nor 190

 

[normmatzen]

All these comments are very interesting.

But, I have a Swiss K-31 which is a 7.6X55 which is a kissing cousin to the 308.

Turns out that the RL-17 is the American name of the powder made in Switzerland and used in the K-31 behind the 175gr bullet.
All loads for the K-31 try to emulate the characteristics of the RL-17. So, I use 175gr SMK's and RL-17 and get the same velocity, 2650 I think, and the same fantastic accuracy as the GP-11 military ammo which is nearly a match load.

Too slow? I don't think so.

In fact, I just built a VZ-24 Mauser with a military 7X57 barrel for a general purpose hunting rifle and QuickLoad thinks RL-17 is the best powder for the 7X57! After trying a bunch of loads, I am a believer1

 

[Laurie]

Hi Norm.

While you might think the 7.5X55mm GP31 is the same, or similar to the .308 Winchester, you're quite wrong!

The 7.5 has a noticeably larger capacity case, 65gn water capacity v the 308's typical 56 gn. That's a 16% volume increase which changes the internal ballistics equation completely.

You may occasionally see queries on the forum about necking the 6.5-284 Norma up to .30 calibre, quite a large cased design. Well .... do so, and you get the 7.5mm Swiss GP31, a fine round, and potentially capable of substantially more performance than the 7.62 X 51mm NATO or .308 Winchester if run at the same pressures.

BTW, I've often advised people that Nitro-Chemie SA's 7.5X55mm GP31 powder was adopted by Alliant ATK as RE17.

So far as 'too slow' for .308 Win + 175s is concerned, well try it my friend. I've tried it with the the 185gn Berger 'Juggernaut' as previously posted, in a real rifle with a real 30-inch barrel, and it gave inferior results to faster burning powders.

You may get different results in a different rifle and barrel, and if so, please feel free to post your results here.

 

[mao0720]

Well the bullets were cheap, and ive got the powder, so I might as well try them. Alliant shows 50grs for 168gr bullets, and 48.7 for 180gr bullets, so I will probable start at about 48 gr and see what happens. I will let you guys know how it does.

 

[normmatzen]

Laurie, true about the case diffwerence between the 308 and the 7.5X55. But, the gentleman was not looking for the BEST powder, but wanted to know if RL-17 (which he had a bunch of) would work. I stand by my answer as I think it would.

I shot a 243 WIN a couple years in long range bench rest till I got a bit smarter and went 6BRX. In thwe 243, I used powders from H4350 to RL-17 and finally H1000. Now, I know apples to oranges and all that, but the RL-17 didn't work as well as H4350 in my 243 shooting 107gr SMK's, but H1000 worked very well.

And, in my 7X57 which has case capacity closer to the 308 than the 7.5X55, QuickLoad favors the RL-17 and that is proven by my test loads.

Maybe not optimum in all, but useful in most.

 

[Laurie]

And, in my 7X57 which has case capacity closer to the 308 than the 7.5X55, QuickLoad favors the RL-17 and that is proven by my test loads.

Precisely - you're agreeing with me. It's the ratio of case capacity / charge weight to bore diameter which is crucial in any powder choice with the third factor of bullet weight (inertia) thrown into the mix.

The 4350s are 'standard powders' for 7X57mm with its significantly smaller bore area and as a result, a very different 'effective expansion ratio' to a similar case-capacity thirty-calibre design. I happily used Viht N160, slower burning still than the 4350s and Re17 in 7X57mm when I used to load the cartridge many years back for a German manufactured South African Mauser 'long rifle', a Boer War relic. I'd never consider even trying N160 in any 308 Win combination even with the new 230gn Berger. Re17 has a similar burning speed to IMR/Accurate/H4350, and insofar as burning rate comparisons are valid, which one must always take with a certain pinch of salt, means it should perform well in the same applications as those powders.

If one takes QuickLOAD calculated MVs as the ultimate indicator of efficiency, a not unreasonable assumption, my experience is that it doesn't always work out that way in practice for some reason with Re17. I'm constantly struck by the number of combinations which the program lists the powder as providing the highest MV, but when I and others try those combinations on the range often find them disappointing. 'In this sort of theory world', 6.5-284 and Re17 should be ideal partners for instance, but not that many people have actually adopted the powder after trying it.

I was surprised and disappointed to find that I got relatively poor results from the powder with the 185gn Berger LRBT 'Juggernaut', sheer MV figures aside. That same rifle and chamber had performed superbly with the apparently similar Viht N550. Do a QuickLOAD propellant table run for 308 with this bullet at 2.900" COAL in a 56.0gn water capacity case and Re17 is apparently right on the money - 1st equal MV (2,811 fps) with W760/H414, 102% fill-ratio, 100% charge burn. It ticks every box. N550 is ~ 60 fps behind, Varget ~90 fps down and N150 is hardly on the radar nearly 200 fps awry.

What do most experienced 1,000yd sling and F/TR shooters use behind this bullet? Viht N150 and N550 in the UK; H4895 and Varget in the US. So far as QuicKLOAD predictions go, UK F/TR competitors obtain MVs from the two Viht powders that are impossible without producing massive charge compression, and which ought to at the least wreck cases in a single firing such are the pressures likely to be generated. So, great and invaluable development tool that QuickLOAD is, this is an application where the program produces misleading results unless some iof its database values are 'tweaked'.