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New GAP

brand692

brand692

Gunny Sergeant
Supporter
Full Member
Minuteman
Oct 22, 2009
1,359
95
45
Western NE
#1
Well, here is my new to me GAP, only had 80 rounds on it when I got it. Different than most of the other precision rifles these days, but a riot to shoot nonetheless.

Remington 700 LA
Obermeyer 5R 11.25 twist, 30 inch, M24 contour, fluted barrel
HS M24 Stock
Badger M4 bottom metal
Badger FTE brake
Badger 20 MOA base
Badger Rings
TIS sling
Harris Bipod with Pheonix Tactical Pod Claws (rubber skis mounted)
PH 3-15x50 Gen II XR with USO Sunshade

100_2552-1.jpg

100_2553-1.jpg

100_2554.jpg


Its chambered for the round on the left. The round on the right is a standard 308W. May not recognize the case....

<div class="ubbcode-block"><div class="ubbcode-header">Click to reveal.. <input type="button" class="form-button" value="Show me!" onclick="toggle_spoiler(this, 'Yikes, my eyes!', 'Show me!')" /></div><div class="ubbcode-body"><div style="display: none;">
100_2556.jpg


300 12 EGG Magnum, a 30-378 max improved. Spent three days and 3 lbs of Retumbo working up a load for it (only 125 rounds). Found a nice slower load using 105 grains of Retumbo, Rem 9 1/2 Magnum primers, and a Lapua 155 Scenar seated with a OAL of 4.148.

Went up to 117gr, but the accuracy wasn't there and I was only gaining .2 mils of elevation at 300M. The case will hold ±130 grains of powder, so I'm a long ways from 100% case capacity. More to follow on development with H-US869 and H-50BMG. Trying to get closer to a full case while maintaining accuracy. I plan to put a chrono on it and see what speeds I'm getting, but I know its fast. </div></div></div>

Thanks to <span style="font-weight: bold"><span style="font-size: 14pt">Bill the Lurker</span></span> for all the range time and borrowed equipment-sorry for the dents in the steel targets; <span style="font-weight: bold"><span style="font-size: 14pt">A10XRifle</span></span> for a fantastic precision rifle, and <span style="font-weight: bold"><span style="font-size: 14pt">264charlie</span></span> for the optics. I really do not have a rifle that is more fun to shoot than this.
 
#11
Re: New GAP

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Mike</div><div class="ubbcode-body">it shoots a 155gn scenar at over 4000fps. Yes, 4000fps. It's 16 moa to 1K </div></div>

DAMN! Now that is movin' right along!!!!

1,000 round barrel life (maybe 1,200)??
 
#12
Re: New GAP

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: TimResin</div><div class="ubbcode-body">Whoa how long does the barrel last? </div></div>
500 rounds on a barrel. Can be set back for another 300. Its toast by 800 though.

But, good news is it has the same BF as a 338 LM, so re-barreling to that is always an option.

Its a blast to shoot.

I only went to 521 yards with it. Even with a light load of 102 grains of Retumbo, it still only needed 1.6 mils to get there.
 
#14
Re: New GAP

Thanks for all the kind words.

I thought that the few "overbore" and "speed freaks" on here would get a kick out of it.

Start with Weatherby 30-378 brass, load 102 grains of Retumbo in it, and fire form it to 300 12 Egg.

I lost 1 out every 10 pieces of brass during the fire-forming process to split shoulders. So, there is some brass loss.
 
#15
Re: New GAP

Speed freak is right...whew. Only downside I guess is that when you drive formula 1 speeds, you've got to change tyres every few laps...or 500 rounds

Would be great to have a load that hammered straight out of the gate, sounds like you've had to use about 1/4 of the current barrel life on load dev. Still, I guess by the time you get the next barrel you'll have a better idea of a good starting point.
 
#22
Re: New GAP

I have to give George the credit on the build and the cartridge, as they were both his design.

The fastest <span style="font-style: italic">accurate</span> rifle I have had was a Hart built 22-250 AI varmint rig. It shot a 40 grain V-Max at 4350 out of 30 inch tube. But, this rifle is nipping at its heals with a bullet that is nearly 4 times the weight.

The trick with this rifle is to keep the bullet seated close to the lands, but still have the huge powder loads-which is tough. Unfortunately, seating them close to, or at the lands yields high pressures too early. On the other hand, jumping the bullets will allow you to put another 11 grains of powder in the case, but accuracy suffers. There is no doubt in my mind that this will drive a 155 at 4,000-maybe 4,100, but I just couldn't get the accuracy out of it at those speeds as it was too much of a jump. Maybe if I try another 155gr projectile that jumps better, I'll have better luck.

Squirrels in any adjoining county don't stand a chance. Its all a matter of finding a tall enough stand to see that far...
 
#25
Re: New GAP

<span style="font-weight: bold">SWEET! </span> You have to have an Escalade or you dont qualify to own that rifle in that caliber.
wink.gif
 
#28
Re: New GAP

el gordo2, That is a great picture. This is the round I PM'ed you a while back about, wondering about how you were loading the 300 Kong. The 12 Egg is very close to the Kong, but as you noticed, it has a shorter neck and will hold slightly more powder. However I have to admit, even though it holds more, I can't get it in there as I start getting pressure signs long before I reach case capacity, at least with Retumbo. I'm going to try the slow 50BMG powders next. Doing the math, I think I'll be able to get somewhere in the neighborhood of 125-128 grains of US869 in it without over pressurizing it. I also have some H1000 but I think that will not be any better than Retumbo.

I compared the 12 Egg to a 6 Dasher case, and the neck lengths are nearly identical. Surprisingly, when reloading, a couple of friends pulled random cases out and they either had no run out, or next none.

I would suspect that the 300 Kong would be less prone to splitting necks during the fireforming process as you are not stressing the brass as badly. When brass is 70 bucks per 20, it sucks to loose one out of ten pieces of brass to split necks.
 
#30
Re: New GAP

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: brand692</div><div class="ubbcode-body">Thanks for all the kind words.

I thought that the few "overbore" and "speed freaks" on here would get a kick out of it.

Start with Weatherby 30-378 brass, load 102 grains of Retumbo in it, and fire form it to 300 12 Egg.

I lost 1 out every 10 pieces of brass during the fire-forming process to split shoulders. So, there is some brass loss. </div></div>
try fireforming with cream of wheat instead of a projectile. will save barrel life and probably prevent case splitting.
 
#36
Re: New GAP

OMG THAT IS RIDICULOUS! I was gonna do a 300WM on a LA Savage but I think this might be the one, That's unbelieveable how fast that thing gets going. Does anybody know how fast this sends the 208 and 210's?
 
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