Reaching 1000 yards

[knor70]

Hello everyone, I am a new member to this forum and have been reloading for approximately eight months. I have just shot out to 1000 yards and am showing signs of high-pressure, i.e. lug marking on the cartage's head and some blown primers.

My weapon is a custom AR 10 w/20" barrel, shooting 308 Winchester, Nosler Custom Competition 175gr bullet, F.C. brass, CCI #200 primer and Varget 44 to 45 grs resulting in approx. 2600+ fps.

Very experienced Long Distant shooters who were pulling targets in the pit stated that it sounded like my round was going subsonic. According to "Lyman's Handbook" I should be well below 59,000 psi. The charge of 45.2+ should get me to 2700+fps (59,300 psi) but I have pressure indications at lower powder volume. I found the following:

http://www.gunnersden.com/index.htm.rifle-reloading-powder.html

In testing this procedure on my brass here is what I found on these cartages at 90% capacity;

Hornady 43.1 grs
F.C 40.9 grs
Rem 41.49grs
Win 42.93 grs

DA....is there any reliable source out there?

Is it possible with an AR 10 adequacy reach 1000 yrds to 1200 yrds??

Thanks in advance.

 

[USSR]

knor70,

Having shot in 1,000 yard competition for 6 years, I can say that the .308 Winchester is a marginal 1,000 yard cartridge to begin with, and when you use a 20 inch barrel you are handicapping yourself all the more. First thing you need to do is ditch the Federal brass. If you can afford it, go with Lapua; if not, then I suggest Winchester. If that doesn't do it for you, then you might want to try the 155gr Scenar bullet. Hope that helps.

Don

 

[Onewolf]

I just started shooting long range a year ago, but everything I have learned indicates that a 308 with a 20" barrel is not what I would choose if I wanted to shoot 1000+ yds with precision/accuracy. You are definitely going to be transonic at that range.

 

[tightgroup tiger]

Have you tried running these loads over a Chrony? I wouldn't necessarily go buy Lyman's pressure and velocity for their publicized loading data as to what your rifle is trying to tell you.

It doesn't work that way. I have a Browning BLR in 30-06 that has an undersized chamber, big time, and is probably the most accurate rifle I have. I have to load 3 full grs under max load because of the pressure this rifle is keeping.

I have
two other rifles that I consistently load 2 grs over pre 1972 maximum loads with no signs of pressure at all.

A 20"barrel in 308 win should be able to get to 1000yd but it would be a reach for it compared to a good 24" or 26" barrel and receiver made specifically for this. A semi auto, Someone else would have to answer for. I have no experience with that one and don't want to comment on it.

 

[ArchAngelCD]

According to Nosler a Max charge of Varget with their 175gr Competition bullets in the .308 Win is 43.5gr. So there is your first problem, you're over on the powder charge. Secondly, does your AR-10 have a commercial chamber or a military chamber. You might be developing excessive pressure there too. Add both together and you might we well over the SAAMI pressure limits, it's no wonder you are seeing pressure problems. DO NOT ignore what you are seeing.

I agree, the .308 is marginal for 1000 yards especially with a 175gr bullet. Sierra has an excellent 155gr HPBT MatchKing bullet and an even better 155gr HPBT Palma MatchKing bullet which is designed for 1000 yard competition. In any event you are killin' yourself with that short barrel.

IMO there are much better choices for the 1000 yard game, something in 6mm or 6.5mm is the new standard in that game from what I know. The 6mm BR is the darling of 1000+ yard shooting. (especially with a 30" barrel) Many are also still using the 6.5-284 which is a good long distance round. IMO most of the 6.5mm cartridges will do a better job than the .308 Win.

 

[Jim Watson]

Using Sierra, not Nosler 175 gr BTHP, I have gotten 2700 fps with 45 grains of Varget... from a 28" barrel on a bolt action. I usually load 44 for 2650 fps and better brass life.
A 155 gr Scenar and 46 grains Varget yields 2900 fps at a BC as high as the 175 SMK.
From a 28" barrel.

Shooting at long range or especially Long Range (NRA 800 - 1000 yds) with an 18 or 20" barrel is kind of a stunt. Usually done with a bolt action that won't show alarming "pressure signs" until heavily overloaded.

I think you would have more fun at 600 midrange with that rifle.