Effective range for 7.62mm...

by Byron, Monday, July 18, 2016, 09:51 (3053 days ago)

We had to opportunity to attend an open range day at the Spearpoint Ranch yesterday and shoot as much as we wanted to at targets from 300 out to 1400 yards spaced at 100 yard increments. I was shooting a Savage "tactical" rifle in 7.62mm shooting 168gr milspec boat tail bullets and my son shooting his AR30 in .300 WM with 190gr Matchking bullets. Both rifles are sub MOA shooters at 100 yards, hot,cold, clean or dirty.

The atmospheric conditions in the morning were perfect and both shots from both rifles were leaving clearly visible traces in the air heading down range.

The 7.62 was absolute dead bang at the 800 yard mark easily hitting 5 for 5 on the 12x18" plates. Past 800 yard it fell completely apart and I never hit a single plate with it past 900 yards out of another 30 or 40 shots.

The trace clearly showed a smooth looped line to the 800 yard targets and then started a big corkscrew that maybe got yaws of 20 to 50 feet across at 1000 or so. It was difficult to judge distance out there but clearly the bullets had gone transonic and became completely unstable. I would have never guessed it would be so dramatic. The rifle/round was shooting probably 6-8" groups at 800 and at 1000 probably opened up to 20 feet or more. Crazy. I would not have believed it if I had not seen it.

The .300 WinMag and 190 gr Sierra Matchkings held up just fine and the silhouettes at 1400 yards were in grave danger with hits maybe half the time even when the wind came up. Still, the bullet was clearly stable all the way out there.

Looks like it time to order a bunch more of the 190s...

Byron

[image]
http://www.spearpointranch.com/dogs.html
http://www.matchgradeprecision.com/precision-long-range/

Effective range for 7.62mm...

by bmize, Monday, July 18, 2016, 11:19 (3053 days ago) @ Byron

I started shooting 1,000 yd F class matches a few years ago.
We have a lot of new guys show up with there tactical 20-24" 308's shooting factory 168's.
the guys shooting the 20" guns usually give up after a dozen or so rounds.
They might get a few on paper(60" paper)but all are coming through sideways.
The 24" guns(unless the humidity is way up) usually can stay on paper, but groups are somewhere in the 24-36" range.
The 168's usually go subsonic somewhere between 900-975yds. You can easily hear it in the pits when they come over your head.
Whats suprising is the 175 factory match ammo hold up at 1k out of the 24" rifles, but I doubt it would make it another 50yds.
All the above is at best I remember 1400' elevation. get on up in the 5-6k range and it will carry a little further.
If you want to shoot 1k with a 308, get a longer barrel and load 175-185 bullets with as much varget as is safe for your rifle.
Just as an example, last weekend a new 308 record was shot at Raton NW, 200-14x (5"x Ring)
Was out of a 30" barrel shooting 185 Bergers

Also, the 155gr match bullets will stay supersonic to 1k when you load them yourself, but are affected much more by the wind.

Interesting reports with REAL data vs theory. Thanks. NT

by Bryan Pettet @, Ft Worth, TX, Monday, July 18, 2016, 11:43 (3053 days ago) @ bmize

-

correction

by bmize, Monday, July 18, 2016, 16:21 (3053 days ago) @ bmize

The above record was shot with the 200gr bergers, not the 185s.
Though most longrange 308 shooters are using the 185's

300 wm load

by bmize, Monday, July 18, 2016, 16:29 (3053 days ago) @ Byron

You should really give the Berger 215 or 230 gr bullets a try.
The guys that shoot the 300WSM in f class swear by them.

Nice!!

by Slow Hand ⌂ @, Indiana, Monday, July 18, 2016, 16:40 (3053 days ago) @ Byron

I have only had the chance to shootout to 350 locally. I normally load 168's for my 20" FN PBR. It's sub MOA out to 350 when I do my part. I have actually been thinking of trying some 155 gr Palmas due to my lack of long distance. I think they even make 135 gr SMK's. Probably more affected by wind, but that's not a huge deal at 350. A buddy is working on a target style AR-10 in .308 and when he gets it finished were headed to a range in northern Indiana that has a thousand yard range. I'm really looking forward to that!

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FN

by bmize, Monday, July 18, 2016, 17:31 (3052 days ago) @ Slow Hand

The FN is a 12tw so the heavies(185's) will not shoot in it, but anything up to 175's will be fine.

Several guys use the 155's on the 600yd matches.
I shot a lot of the 155 bergers out of my FN before I rebarreled it.
There are a few F Class matches in IN and OH every month, you need to go check one out.

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