Zak Smith
Member
Going back in time a bit, I bought my first serious bolt gun in early 2005 in preparation for the ITRC. Prior to pulling the trigger on the AI-AWP (308), I had been considering having a gun built in one of the 7mm magnums (7RM or 7WSM), since some of my friends were using those at the time for long-range practical shooting. 7mm Wsm For Long-range ? - THR
; Zak's 2004 ITRC Report - THR
; New boomstick: AI-AWP (PICS) - THR
; Zak's 2005 ITRC Report - THR
After shooting the AWP in 308 for about a year, I found a used AI-AW and had GA Precision cut a .260 Remington barrel for it. I used this rifle at the 2006 and 2007 Steel Safari matches with great success. Earlier in 2007, I used a 6.5x47 Lapua barrel on my original AWP at the Camp Guernsey Invitational Multigun. Accuracy International AW in 260 Rem (PICS) - THR
article | The Case for .260 Remington: A Better Cartridge For Practical Long-Range Shooting
article | Steel Safari 2006
article | Blue Steel Ranch 2007 Steel Safari Practical Rifle Match
In the meantime, I had been shooting a AI-AWSM in .338 Lapua Magnum since late 2005. The .338 is one heck of a long-range cartridge, slinging a high-BC 250 gr bullet at 3000 fps, or an even higher 300-grain SMK at about 2700 fps. Accuracy International Super-Magnum AWSM 338 (PICS) - THR
One problem is that the 338LM is not allowed in many long-range matches due to the (sometimes correct and sometimes incorrect) assumption that is causes target damage. As materials prices have risen and the $USD has become weaker, 338LM has gone from "expensive" to "really expensive" to shoot.
The "long action" AI-AWM/AWSM is available in both .300WM and .338LM from the factory, and a user can switch between these two with a bolt body, barrel, and magazine change. But I didn't want 300WM; I've been thinking about 7RM for a long time. Since 7RM shares the same case head size as 300WM, a conversion to 7RM was straightforward. I would get a 7RM barrel and use the 300WM bolt body and magazines from AI.
Again, I went to GA Precision for a custom barrel ready to screw onto my action. The 7mm barrel finished at 26" with a heavy Palma profile for weight savings. This tapers quickly down from 1.2 to 1.0, and has a slow taper to 0.90 just before the sleeve cut for the AI muzzle brake. The barrel has a twist and chamber set up specifically for the 180-grain Berger VLD (BC 0.684).
Here's how the gun turned out with the new barrel:
............... Larger version of above photo.
The gun feels lighter and easier to handle with the lighter barrel and the big 5-25 S&B swapped out for a 3-12.
............... Larger version of above photo.
I actually had two 7mm RM barrels made: one for me, and one for by buddy who has an AWM (300). At this point we both have 300 and 338 bold bodies, and he's been shooting 338LM off and on for about a year, though he did have to use his 300WM barrel at the 2008 Steel Safari due to match rules. We have plans to use these rifles in 7RM to shoot some elk this fall.
Under the spare 7mm barrel, there is the original 338LM barrel. Note the difference in barrel profile (and its weight implications). Then we have the 338LM bold body, the AI barrel changing tools, four 7mm RM rounds, and my TBAC 30P sound suppressor (which works great on the 7RM, but gets hot very fast).
............... Larger version of above photo.
Here's how the 7RM stacks up ballistically to the best loads in some other calibers:
What's interesting is that the 7RM shooting the 180's beats the 300WM shooting the 210's for wind and drop with more than 25% less recoil.
Other threads about 7mm Remington Magnum:
7mm Remington Magnum - THR
The 'ideal' sniper rifle... whoda thunk? - THR
Long range targets and 7mm rem. mag. - THR
Long range shooting advice needed!! - THR
Long range targets and 7mm rem. mag. - THR
For load development, I started with Winchester cases, 215M primers, the 180gr Berger VLD, and Retumbo. I started off at 64 gr to be safe, but continued a progression up to as high as 2950 fps. I backed down from this to about 2900 fps.
I shot about 30 rounds during this load development, then took the rifle to Raton for the July Sporting Rifle Match, where I shot all 100 rounds I took down there. Based on the computer data vs. the actual dope, either the velocities increased a little bit as the barrel broke in, or the computer data is running a little low. Recoil is very mild, and shooting with the suppressor feels very similar to the suppressed 260, just a little more push. Spotting my own hits is no problem.
I'll post updates to this thread as I get more confirmed data and more time with this rifle in field-style matches.
; Zak's 2004 ITRC Report - THR
; New boomstick: AI-AWP (PICS) - THR
; Zak's 2005 ITRC Report - THR
After shooting the AWP in 308 for about a year, I found a used AI-AW and had GA Precision cut a .260 Remington barrel for it. I used this rifle at the 2006 and 2007 Steel Safari matches with great success. Earlier in 2007, I used a 6.5x47 Lapua barrel on my original AWP at the Camp Guernsey Invitational Multigun. Accuracy International AW in 260 Rem (PICS) - THR
article | The Case for .260 Remington: A Better Cartridge For Practical Long-Range Shooting
article | Steel Safari 2006
article | Blue Steel Ranch 2007 Steel Safari Practical Rifle Match
In the meantime, I had been shooting a AI-AWSM in .338 Lapua Magnum since late 2005. The .338 is one heck of a long-range cartridge, slinging a high-BC 250 gr bullet at 3000 fps, or an even higher 300-grain SMK at about 2700 fps. Accuracy International Super-Magnum AWSM 338 (PICS) - THR
One problem is that the 338LM is not allowed in many long-range matches due to the (sometimes correct and sometimes incorrect) assumption that is causes target damage. As materials prices have risen and the $USD has become weaker, 338LM has gone from "expensive" to "really expensive" to shoot.
The "long action" AI-AWM/AWSM is available in both .300WM and .338LM from the factory, and a user can switch between these two with a bolt body, barrel, and magazine change. But I didn't want 300WM; I've been thinking about 7RM for a long time. Since 7RM shares the same case head size as 300WM, a conversion to 7RM was straightforward. I would get a 7RM barrel and use the 300WM bolt body and magazines from AI.
Again, I went to GA Precision for a custom barrel ready to screw onto my action. The 7mm barrel finished at 26" with a heavy Palma profile for weight savings. This tapers quickly down from 1.2 to 1.0, and has a slow taper to 0.90 just before the sleeve cut for the AI muzzle brake. The barrel has a twist and chamber set up specifically for the 180-grain Berger VLD (BC 0.684).
Here's how the gun turned out with the new barrel:
............... Larger version of above photo.
The gun feels lighter and easier to handle with the lighter barrel and the big 5-25 S&B swapped out for a 3-12.
............... Larger version of above photo.
I actually had two 7mm RM barrels made: one for me, and one for by buddy who has an AWM (300). At this point we both have 300 and 338 bold bodies, and he's been shooting 338LM off and on for about a year, though he did have to use his 300WM barrel at the 2008 Steel Safari due to match rules. We have plans to use these rifles in 7RM to shoot some elk this fall.
Under the spare 7mm barrel, there is the original 338LM barrel. Note the difference in barrel profile (and its weight implications). Then we have the 338LM bold body, the AI barrel changing tools, four 7mm RM rounds, and my TBAC 30P sound suppressor (which works great on the 7RM, but gets hot very fast).
............... Larger version of above photo.
Here's how the 7RM stacks up ballistically to the best loads in some other calibers:
Code:
_Bullet_ _BC_ _MV_ 0 250 500 750 1000 1250 | YARDS
338 250 0.675 2950 > 0.00 2.64 11.17 26.67 50.49 84.30 | wind (inches)
7RM 180 VLD 0.684 2900 > 0.00 2.67 11.28 26.93 50.95 85.00 | wind (inches)
300WM 210VLD 0.647 2900 > 0.00 2.83 12.01 28.76 54.66 91.57 | wind (inches)
300WM 190VLD 0.590 3050 > 0.00 2.90 12.37 29.80 56.99 96.16 | wind (inches)
260 140 0.610 2830 > 0.00 3.12 13.29 32.01 61.18 102.87 | wind (inches)
308 155 0.508 2900 > 0.00 3.66 15.82 38.68 75.13 127.84 | wind (inches)
308 175 0.51* 2650 > 0.00 4.27 18.56 45.74 89.14 150.37 | wind (inches)
338 250 0.675 2950 > -0.00 0.59 2.24 4.27 6.73 9.70 | drop (mil)
7RM 180 VLD 0.684 2900 > -0.00 0.62 2.33 4.43 6.96 10.02 | drop (mil)
300WM 210VLD 0.647 2900 > -0.00 0.63 2.36 4.51 7.14 10.35 | drop (mil)
300WM 190VLD 0.590 3050 > -0.00 0.55 2.13 4.14 6.64 9.75 | drop (mil)
260 140 0.610 2830 > -0.00 0.69 2.54 4.88 7.78 11.38 | drop (mil)
308 155 0.508 2900 > -0.00 0.66 2.53 4.98 8.16 12.33 | drop (mil)
308 175 0.51* 2650 > -0.00 0.87 3.17 6.24 10.28 15.61 | drop (mil)What's interesting is that the 7RM shooting the 180's beats the 300WM shooting the 210's for wind and drop with more than 25% less recoil.
Other threads about 7mm Remington Magnum:
7mm Remington Magnum - THR
The 'ideal' sniper rifle... whoda thunk? - THR
Long range targets and 7mm rem. mag. - THR
Long range shooting advice needed!! - THR
Long range targets and 7mm rem. mag. - THR
For load development, I started with Winchester cases, 215M primers, the 180gr Berger VLD, and Retumbo. I started off at 64 gr to be safe, but continued a progression up to as high as 2950 fps. I backed down from this to about 2900 fps.
I shot about 30 rounds during this load development, then took the rifle to Raton for the July Sporting Rifle Match, where I shot all 100 rounds I took down there. Based on the computer data vs. the actual dope, either the velocities increased a little bit as the barrel broke in, or the computer data is running a little low. Recoil is very mild, and shooting with the suppressor feels very similar to the suppressed 260, just a little more push. Spotting my own hits is no problem.
I'll post updates to this thread as I get more confirmed data and more time with this rifle in field-style matches.
