Need help me with my F-Class build, which 7mm cal to use????

E

elmerdeer

Guest
Hi guys I am going ahead with an F-Class build, and my main problem is which 7mm caliber should I use? Has anyone used a 280AI for F-Class as I have the reamer and my gunsmith can throat it for the 180 Berger hybrid or another bullet with extremely high b.c, like the new Sierra's? I would like to be able to get speeds of 2950 to 3100 maybe, can I achieve that with the 280AI? Or do I have to go bigger?
Anyway I am just looking for the best option, that expierenced F-Class shooters are using.
Thank you
Elmer
 
i have heard of .284, and 7mm shortmag. try on 6mmbr forum under competition. the guy that won the sw nationals i heard shot a 7rsaum. 180 bergers.
 
http://www.accurateshooter.com/cartridge-guides/7mm/

they are all discussed on this article. I shoot both 7WSM (true 7WSM) and .284 Winchester; my brother shoots .284 Winchester in F-Class. I love them both. If you are going to shoot the180 grain Bergers or JLKs or the 189 Cauterucio, you want the 2,800 to 2,900 fps node. its a true hammer. more importantly is has 1/4 less wind hold than a 6.5x284 and nearly double the barrel life (depending upon who you ask).

Jeffvn
 
My vote is for the 284 Winchester as I just had one built for F-Class Open at 1000 yards.

The 7mm WSM intrigues me as short fat cases seem to shoot better than longer cases with the same capacity. BUT, I wanted the ability to change calibers should the 284 not work out and the 284 uses a "normal" bolt face that is common with 308, 6mmBR, etc. so I had a drop back planned if needed. Now that the 284 Winchester is here and I have started working it during the break in phase, I am VERY pleased with it as it is shooting under 1/3 MOA out to 600 yards with the Berger 180 gr Hybrid and H4831SC with Wolf primers and Lapua cases.

I have not been able to stretch its "legs" yet at 1000 yards but that is next.

George
 
I have not seem many postings about the .284 Shehane recently. Are people getting all the velocity they need out of the 'standard' .284 Win or has it simply lost interest?
 
The local guys shooting the Shehane version of the 284 are having real problems with vetical grouping at 1000 yards. The standard 284 is not having this problem.

I get all the velocity I need from my 284. Remember that you can load the snot out of these cartridges and not really get that much more performance while eating your barrel and brass up.

The difference between a moderate load and a real HOT load in a 284 Win is less than a half MOA at 1000 yards with a full value 10 mile per hour wind.

George
 
You might think about a 280 Rem Ackley Improved.
That is what I am building right now.
Hoping to get close to 3000 FPS with 30 inch barrel.
 
Thank you, George.

I had wondered why I had not seen much about the Shehane of late and noted that the velocities people were quoting for the .284 Win were not that different from those of the Shehane...and then there is the matter of dies.

I imagine that you are quite happy with yours if it holds vertical well.

I may have missed an earlier comment, but are you using H4831SC?

Thanks,

Rick
 
Rick, yes I am using H4831SC. The load I have been shooting is 54.2 gr, but the velocity is 2660 and I would really like closer to 2800 fps.

George
 
Jdaniel343 said:
You might think about a 280 Rem Ackley Improved.
That is what I am building right now.
Hoping to get close to 3000 FPS with 30 inch barrel.
Click to expand...

J

If you intend to shoot the 180 Berger VLD I doubt if you'll get to 3000Fps. Maybe 2850. Walt recommended 2800 to 2850 with his bullet and I think you'll find that's where it works the best.

JMHO

Ray
 
If you use a .284 Win it will require the bullets to seated with the boat tail bearing surface juncture at or infront of the neck shoulder juncture otherwise you may have fliers.
This is being said from experience. Bullets seated at this depth will not fit a factory SA magagine.
Nat Lambeth
 
After 5 284 barrels, I have settled on 2820 fps (and even a 2700fps load for light conditions when we are going for Xs). I have tried 2950 fps in each of them but it was never consistant and was hard on the brass.
I think the reason the Shehanes have lost popularity, is that you still have to realy push them hard to get to 2950 fps, so people switched to 280AIs and RSAUMs to get to 2950 consistantly.
At 2820 fps, a 284 barrel will last a few thousand rounds and recoil is not too bad.
Jumping up to 2950 fps seems to bump recoil up more than recoil sensitive people like me would like, though some love the thump.

I,m thinking of getting a barrel to reach 2950 fps with 180s for the realy bad conditions or when shooting long range F class to 1 mile, and would go for something like a RSAUM or WSM which will do it without having to push pressures.

So, what are the wind conditions like where you shoot? If it is calm and easy like where I live, then a tack holing 284 is the go. If you live in an area where the wind is strong and tricky, a 280ai or RSAUM will be better.
 
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Have a look at:

http://www.accurateshooter.com/forum/index.php/topic,3762313.0.html

The 280AI is an attractive option for people with a suitable action and who don't want to go down the magnum bolt-face route. It can also be formed out of Lapua or any other good quality .30-06 brass, in slightly short-necked form, and PT&G has at least one reamer design in its list for just such a version. Unlike the .284 Shehane it has reasonably priced dies listed for it too - custom job in the Shehane case.
 
Just an observation. I May have been the first to champion the 284 Shehane in prone competition at 1000. I went to this chambering because I knew that the 7mm was the best balistic product till you got to heavy 30 cal bullets. With a standard bolt face, I have had no problem in reaching 2950 with 57 grains of H4350 in three of the four Shehane barrels I have had. One of the barrels was very slow and not accurate on top of that -- it is now a tomato stake.

I hear the stories about vertical from the F-Class shooters, and some have told me that they shoot the Shehane just like their Dashers -- can't do that! I am a big guy. Recoil does not bother me at all in the prone. I also sling up VERY tight. I have NEVER shot a Shehane in F-Class, but I have shot a 300 WSM in F-Class. You have to hold on to the larger chamberings, and your technique needs to be rock solid consistent. If you have your bags packed too tight, or you shoot a heavy recoiling rifle like a Dasher, you will get vertical every time.

Bill Shehane went with his improvement to allow a quicker cycle on a quick run with his Bench guns -- not for the increase in case capacity. I went with the 284 Shehane because it would allow a higher node without blowing primers. Three years ago this weekend, I broke Mid-Tompkins NRA SR. 1000 prone record with metalic sights by shooting a 200-14X (since bested by an X) This was the same weekend that Charles Ballard broke the F-Class record (maybe the same relay). I went into that match with a gun that give me 2951 with an ES of 3 over a 20 shot test (NOT SD, but ES). The temp was 105 degrees at Camp Butner. A lot of people blew primers that day, but not my Shehane. That is why I went to that chambering and it gave me exactly what I wanted. My fire forming load starts where the straight 284 is pushing hard -- 54g H4831SC

The real problem with the Shehane is the dies and the fire forming. Expensive and time consuming. No question. But I love the prep work anyway so no problem for me. If you would rather not go through all the initial prep and custom dies (Carstensen and Warner for me and I also own my own reamer), the straight 284 is the way to go.

If you have a Magnum bolt face, the RSUM is very attractive. I have never shot one, but I have been told by a VERY good source that the barrel life is significantly better than the WSM based 7mm chamberings.

I believe that the first 11 places in the World F-Class were 7mm chamberings. Third place (I think) was a Shehane. The 7mm is here to stay in F-Class but you must learn how to drive the larger chamberings.

You really can't make a wrong decision here. Another thought (just mine): Never build a gun you can outshoot as that gun will lie to you on the 1000 yard target.

Jim Hardy
 
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Jim,

Its interesting to hear you talk about the need to drive the gun differently for the magnums... @ Butner in 2009, I shot one day paired up with Stan Rogers, and besides the beautiful fit-n-finish on his gun - a .300WSM running B210VLD - I noticed it had a vertical fore-grip to help tame the jump/torque. At the time it struck me as very odd, to say the least. Turns out that was his son's gun... I forget why Stan was shooting Derek's gun and what not. The next year @ Sacramento in March, Derek used that same gun to win the FCNC, and if I'm not mistaken, Derek uses a similar fore-grip setup on his F/TR gun with pretty good success. It certainly looks strange to see a belly gun with a fore-grip like an M4, but apparently it can be effective!

Monte
 
Monte:

If it is within the F-Open rules, I suspect that you will start seeing more off-set fore ends on stocks to account for the torque of the magnums. I know you shoot sling as well so you know how much easier it is to control the recoil than with the F-Class rig. In F-Class (and 1000 yd BR) it is not only important that your gun balances and tracks in the bags when you setup, it must balance and track under recoil. The less you have to adjust your setup after each shot, the better your chance to stack you shots and keep the target in the pits.

By the way, not giving advice here as my F-Class experience does not qualify me to cary your gear to the line, but I have wanted to share my experience with heavy recoil from the prone and F-Class. Opinions may be contrary.

Jim
 
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