308win 175gr velocity

[Nude nut]

Hi,
what velocity do you stive for with 175gr bullet in a 308win.
I grabbed some 175gr otm bergers to try in my 32in 1.13 twist barrel did a velocity/pressure test today got up to 2820fps no pressure sighns at all.
Running palma brass cci450 and 2208/varget I certain more is there to be had I generaly shoot 155.5 fullbores in f/standard here in Australia .
Im switching over to FTR and have no hesertation in using the 155.5 for most part out to 900y.
Maybe when I get a faster twist barrel I may try a better bullet heavier bullet.

Cheers Trev.

 

[Ned Ludd]

With one rifle I have that has 28" 10-twist barrel, there is a nice node around around 2810 fps with H4895, also using Berger's 175 OTM bullet. In that rifle, which has a fairly short freebore (0.085"), predicted pressure (QL) is right at SAAMI MAX (62K psi). Nonetheless, Palma brass can withstand those pressures for many firings. Although Varget loads typically tune in about 20 fps slower than H4895, it wouldn't surprise me if your longer 32" barrel tuned in just a bit faster and at lower pressure; 2820 fps is approximately the velocity I'd anticipate.

If your setup likes the 175 OTMs, you might think about trying the 168 Hybrids. With a 32" barrel, I'd expect them to tune in with Varget somewhere in the 2900 fps range. The 168 Hybrid has a very high BC for its weight, very close to that of the 175 OTM, maybe even a tick better according to Labradar velocity data. But because of the lighter weight, you can gain an extra 80 to 100 fps velocity without having to go to substantially higher pressure, which means slightly less wind deflection than the 175s running at a slower velocity. I've used a 168 Hybrid/H4895 load a few times in local F-TR matches from a 30" barreled F-TR setup (11-twist) that also has the fairly short (0.085") freebore with good results. Although something like the 200.20X bullet can shoot quite well out of an 11-twist barrel, the 0.085" freebore of that specific rifle is a deal breaker for me with a bullet that long. For that reason, I specifically worked up the 168 Hybrid load because it allows me to shoot that particular rifle with a short freebore in club matches without being grossly outgunned by F-TR shooters using 200 gr bullets.

 

[Laurie]

If your setup likes the 175 OTMs, you might think about trying the 168 Hybrids. With a 32" barrel, I'd expect them to tune in with Varget somewhere in the 2900 fps range.

I'd second the suggestion to try the 168gn Hybrid. Alongside the 155.5 BT this was my favourite bullet in my final days of shooting F/TR and it won me many medals.

In a 32-inch 10-twist Broughton which was getting a bit long in the tooth, I ran this bullet at 2,960 fps MV. (When the barrel was younger with a less eroded leade it was 25-30 fps faster.) I'll stress though that this was in UK temperatures which we describe as 'usually cool' but which those like Michelle Gallacher and her mum Nancy Tomkins once described as 'freezing' to me in what was a Scottish heatwave!)

This was with small primer Lapua brass, CCI-BR4, and 46.6gn Reload Swiss RS52, a Europe only powder from Nitrochemie. To envisage RS52 think Nitrochemie manufactured Alliant Re17 but with VarGet's burning speed. It is therefore double-based (or 'high-energy' as Nitrochemie insists on calling it, the nitroglycerin added at a late process stage as per Viht N500 series propellants) and employs the 'EI' infused deterrents system. Having tried it against VarGet in various cartridges and loads I found that where one works well so does the other and the charge weight to MV relationships are close. The Swiss grade will allow higher slightly charges though and thereby outperform VarGet, in the case of 308 with this weight bullet by 25-40 fps maybe.

So I'd expect VarGet to be able to run this bullet at wherever the node is a bit either side of 2,900 fps in this barrel length.

One thing I found with the 168 was that it wouldn't shoot well for me with the usual amounts of jump in the 5 to 20 thou' range. Put it modestly into the lands as per a VLD and its grouping was transformed. Another couple of Brit F/TR shooters I know who tried this Hybrid for a while found the same thing. (Every Hybrid I've tried to date - and that's not many being a poor man with huge stocks of older pre-Hybrid types that'll see my shooting years out - seems to behave differently with regard to bullet seating position.)

 

[Nude nut]

Thanks for the info I was going to try the 168 hybrids but Im not sure if the 1.13 twist will do the job .
I run 2206h/h4895 with the 155.5 havnt tried it with 175 yet.
Im at 44.6 with 2208 with a bto of 2.048 at 10thou off the lands OAL of 2.856 with the 175.
Cheers again for your info.

Cheers Trev.

 

[Nude nut]

Laurie thanks for your reply always informative as usual.

cheers Trev.

 

[3Sigma]

Given your barrel length, you are about the same as I on a 24" bbl using Sierra 175 MK. I'm around 2630 fps (not pushing hard) with 20-25 fps per inch is right around your velocity. Now, yours might tune at a different node, but I would say you are in the ballpark.

 

[Michael C]

Last weekend I shot the 168 Hybrid out of a 32” 1x13 twist palma rifle that I converted to FTR. Shot a 3x1000 in Sacramento, CA. 46.3g Varget, unknown speed and zero load development and it shot amazingly well. It’s a short chamber (2011 palma reamer) and so the bullets are deeper than I wold like but I feel like that bullet has potential in a chamber that is not optimal for FTR shooting. First match with this set up (I normally shoot Palma rifles) and just wanted to have some fun. Elevation was very good when I did my part. I was learning how to handle the gun so I lost a bunch of points on the first string. But after that (considering it was averaging 3-8 minutes of wind and gusting a bit higher and also down to 1 minute at one point) I was very happy with it. That bullet is helping me to use a rifle that does not get any use anymore and the barrel is still healthy enough to use up.

 

[Michael C]

I happened to chrono this load yesterday and it was 2960 on a lab radar. 1371 at the target on a shot marker with SD of 7.7. I was shooting at 1000 again in Sacramento. 20 shot string.

 

[SPQR70AD]

I happened to chrono this load yesterday and it was 2960 on a lab radar. 1371 at the target on a shot marker with SD of 7.7. I was shooting at 1000 again in Sacramento. 20 shot string.

with the excellent velocity you are getting out that musket barrel have you ever tried the hornady 208 gr ELD? it has an amazing BC of .690 much better then the 175. you must know that but would love to see the difference at 1000 yds in drop and accuracy with the 208's if you made some loads

 

[3Sigma]

They are running 1:13 twist. I imagine they would already run heavier bullets if they could.

 

[10XSHOOTER]

42.0 of IMR 4064 in a 22" barrel gives me 2630 fps. Krieger 1-10 5R. Winchester brass and a Fed 210M. Sierra 175 MK.

 

[Michael C]

with the excellent velocity you are getting out that musket barrel have you ever tried the hornady 208 gr ELD? it has an amazing BC of .690 much better then the 175. you must know that but would love to see the difference at 1000 yds in drop and accuracy with the 208's if you made some loads

I was just offering an alternative to the 175g bullets. The 168 Hybird is an excellent bullet for longer ranges and wanted the original poster to know about an alternative. For me, I am limited by the 13 twist, and short 2011 Fullbore reamer, which is a match reamer for us sling and irons guys that shoot Palma and Fullbore. We are required to use 155g bullets out to 1000 or longer if in England. In in my case, that bullet helps to use a rifle that was not getting used.

 

[Nude nut]

I was just offering an alternative to the 175g bullets. The 168 Hybird is an excellent bullet for longer ranges and wanted the original poster to know about an alternative. For me, I am limited by the 13 twist, and short 2011 Fullbore reamer, which is a match reamer for us sling and irons guys that shoot Palma and Fullbore. We are required to use 155g bullets out to 1000 or longer if in England. In in my case, that bullet helps to use a rifle that was not getting used.

Good to know that the 168 hybrid will run in a 1.13 twist I do plane to get faster twist later down the road.

cheers Trev.