Apex Afterburner 6.5mm, .277, 7mm, and 338 bullets

yorketransport

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I've had a few of the newer Afterburners from Apex in my hands for a while now, but I'm just getting time to start working with them now. I posted this somewhere else too, but thought I'd post it here as well. I have the 102gr 6.5mm, 103gr .277", 117gr 7mm, and 200gr .338" to try out. I'm just starting to work on loads with each bullet, I'll play around with testing expansion later.


102g 6.5mm

I'm going to test these at the low end out of a 6.5 Grendel, and the top end out of a 6.5/338 RUM improved. I just got my first round of testing with the Grendel done today. Here's what I have so far.

6.5 Grendel (CZ 527 with 19" Blackhole barrel, 1:8" twist)
Hornady brass
CCI 450 primer
H335 powder
102gr Apex Afterburner
2.265" OAL

27.4gr - 2408 fps
27.8gr - 2479 fps
28.2gr - 2501 fps
28.6gr - 2561 fps
29.0gr - 2606 fps
29.4gr - 2617 fps
29.8gr - 2670 fps
30.2gr - 2712 fps

I didn't shoot these for groups, just velocity. The 30.2gr charge still didn't show any pressure, so I'll probably try bumping it up a little more. I don't know if I'd go much higher in a gas gun, but I'll push the bolt action a little harder than I would an AR.

103gr .277

I have some of these loaded in a 270/338 RUM improved, but I haven't shot them yet. I expect to be around 4000 fps from a 25" barrel with the 103s. I'm working on getting my hands on a 6.8 SPC to test them at the low-end velocities. I'll add the results for the .270 bullets when I get them.


117gr 7mm

I'll be shooting these in a 19" 284 Win specialty pistol, and a 26" 7mm SAUM. I haven't shot any of the loads in the 7mm SAUM yet, but I have shot them in the 284 Win.

284 Win specialty pistol (18" McGowen barrel, 1:9" twist)
Lapua Brass
CCI 200 primer
Reloader 15.5 powder
117gr Apex Afterburner
2.922" OAL

50.0gr - 2822 fps
50.5gr - 2902 fps
51.0gr - 2940 fps
51.5gr - 2971 fps
52.0gr - 3043 fps
52.5gr - 3060 fps
53.0gr - 3074 fps
53.5gr - 3102 fps
54.0gr - 3145 fps
54.5gr - 3193 fps

The 54.5gr load was just starting to show a drag on bolt lift, so I stopped there. Those loads were all shot at 100 yards and gave a 1"group for all 10 shots fired. I went back out and tested a charge of 54.2gr of Reloader 15.5 with the 117gr Afterburner at 3165 fps and shot a few groups withouth the Magneto strapped to the barrel. The result was 3 separate 3 shot groups right at .5 MOA at 215 yards, which is about what I've come to expect with this barrel these days. For reference, my standard load in this gun for years has been a 168gr Berger VLD at 2670 fps. It has typically shot better with pretty moderate loads. I'll head out again and try shooting at 500+ yards on the next trip out.

200gr .338

The goal is to test these in a 338/375 Ruger specialty pistol for the low end and a 338/408 Improved speciatly pistol for the high end velocities. I have a 338 Win Mag rifle sitting around too, but those velocities will be very similar to the velocities from the 18" 338/375 Ruger specialty pistol. I've run the first ladder in the 338/375 already, but haven't had time to go for a second trip out with them. For reference, the case capacity of the 338/375 Ruger is in the same range as the 340 Weatherby, 33 Nosler, and 330 Dakota. This data might be helpful for anyone shooting one of those.

338/375 Ruger specialty pistol (18" Benchmark barrel 1:9.3" twist)
Hornady brass (375 Ruger necked down)
Fed 215 primers
Reloader 15.5 powder
3.415" OAL

70.0gr - 2735 fps
71.0gr - 2765 fps
72.0gr - 2833 fps
73.0gr - 2904 fps
73.5gr - 2905 fps
74.0gr - 2916 fps
74.5gr - 2970 fps
75.0gr - 2984 fps

I was hoping to get 2950 fps with the 200gr Afterburner, so I'm happy with the velocities I saw. There were no pressure signs, so I'll try loading a few more at a higher charge for the next trip out. If I can get .5 MOA accuracy at 2975-3000 fps, I'd be extremely happy. My standard target load in this gun is a 250gr SMK at 2645 from the 18" barrel. Gaining 300 fps by dropping 50gr of bullet weight makes a pretty big difference. This is my mid-long range (400-750yard) hunting pistol, so velocity and BC are both a consideration with this gun.

I'll update this thread as I get more shooting done. I'm just starting to slow down at work so I have more time, but now I'm at the mercy of the weather.

Here’s a picture of the cartridges I’m going to test the bullets in. That’s a 338/408 Improved, 338/375 Ruger; 270/338 RUM improved; 284 Win, 7mm SAUM; 6.5/338 RUM improved, 6.5 Grendel.

 

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Willys

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Always enjoy your tests Yorke! Been thinking about those Apex for 338 wm.
 

yorketransport

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A few updates for anyone interested. I shot the loads in the 7mm SAUM and 270/338 RUM improved and did a second round of shooting with the 200gr 338.

117gr 7mm
7mm SAUM 26" Mcgowen barrel (1:9" twist)
Norma brass
Fed 215 primers
Reloader 15.5 powder
2.781" OAL

54.0gr - 3233 fps
54.7gr - 3301 fps
55.4gr - 3347 fps
56.0gr - 3384 fps
56.5gr - 3424 fps
57.0gr - 3433 fps
57.5gr - 3476 fps

The highest charge I tested didn't show any obvious pressure signs and could probably be pushed harder. I'm pretty happy with that velocity though, so I don't think I'll push too much harder.

102gr .277

These were shot in a 26" 270/338 RUM improved with a 1:8.5" twist Broughton barrel. I used IMR 7828ssc for these loads. I won't post up the charges I used, but the high velocity I hit was 4225 fps. I settled on a velocity of 4160 fps that gave .75 MOA groups at 220 yards. I'll try shooting a gel block with this load when the weather cooperates.

200gr .338

I did a second round of testing with the 200gr Afterburner in the 338/375 Ruger pistol to see how the previous load would perform. I settled on 75.4gr of Reloader 15.5 and got a velocity of 3015 fps from the 18" barrel. The 3 groups I shot at 220 yards averaged .5 MOA. With this velocity, the 200gr Afterburner will out perform my standard load in this gun, the 250gr SMK, by nearly 8 MOA of drop at 1000 yards, and should retain a slightly higher impact velocity. I'll need to do more testing to confirm it, but that could make the 338/375 pistol a legitimate 1000 yard hunting weapon, based on the Afterburner's ability to perform at lower impact velocities.
 

Willys

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A few updates for anyone interested. I shot the loads in the 7mm SAUM and 270/338 RUM improved and did a second round of shooting with the 200gr 338.

117gr 7mm
7mm SAUM 26" Mcgowen barrel (1:9" twist)
Norma brass
Fed 215 primers
Reloader 15.5 powder
2.781" OAL

54.0gr - 3233 fps
54.7gr - 3301 fps
55.4gr - 3347 fps
56.0gr - 3384 fps
56.5gr - 3424 fps
57.0gr - 3433 fps
57.5gr - 3476 fps

The highest charge I tested didn't show any obvious pressure signs and could probably be pushed harder. I'm pretty happy with that velocity though, so I don't think I'll push too much harder.

102gr .277

These were shot in a 26" 270/338 RUM improved with a 1:8.5" twist Broughton barrel. I used IMR 7828ssc for these loads. I won't post up the charges I used, but the high velocity I hit was 4225 fps. I settled on a velocity of 4160 fps that gave .75 MOA groups at 220 yards. I'll try shooting a gel block with this load when the weather cooperates.

200gr .338

I did a second round of testing with the 200gr Afterburner in the 338/375 Ruger pistol to see how the previous load would perform. I settled on 75.4gr of Reloader 15.5 and got a velocity of 3015 fps from the 18" barrel. The 3 groups I shot at 220 yards averaged .5 MOA. With this velocity, the 200gr Afterburner will out perform my standard load in this gun, the 250gr SMK, by nearly 8 MOA of drop at 1000 yards, and should retain a slightly higher impact velocity. I'll need to do more testing to confirm it, but that could make the 338/375 pistol a legitimate 1000 yard hunting weapon, based on the Afterburner's ability to perform at lower impact velocities.
8 moa! Whoa!
 

InGodsCountry

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I need to look into those afterburners in my .338 setup. That’s impressive. Thanks for sharing.


Sent from my iPhone using Tapatalk
 

Mark Dille

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Twist needed for 338?
The twist needed for the 200gr is only 1:11" and is a result of maximizing relatively short SAAMI requirements for the 338 WM or even the 338 Federal. This bullet really hits a sweet spot for many 338s out there and is a perfect option for hitting the African plains or the Rockies for up close shots on heavy-bodied animals, or out at longer ranges on softer, smaller targets. Here's a bit more info on it here:

 

yorketransport

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I got some more shooting done with the .277, 7mm, and .338 Aftreburners the other day. The goal on this trip out was to recover some bullet shanks after high-velocity impacts and shoot the bullets at longer range.

I shot all three bullets into 10% ballistic gel at 25 yards, with a stack of leather behind them to catch the shank. My gel blocks have been melted down so many times that It's not worth trying to take pictures of the wound channel. They looked the same as all the other tests I've done with these bullets in gel. The petals completely separate at about 4" of penetration, then follow the shank as they penetrate on. Here are the recovered shanks.

Left to right: 103gr .277; 117gr 7mm; 200gr .338
DfFgrBk.jpg

67DELKG.jpg

vEdgv4r.jpg


These are the approximate impact velocities, and the weight of the recovered shank.

.277- 4080fps 61.8gr
.284- 3430fps 77.4gr
.338- 2975fps 148.1gr

The next part was to shoot the bullets at longer ranges. This is my first trip out with any of these bullets beyond 200 yards. All of the guns were zeroed at 100 yards. I only had 3 rounds left for the .270, but the rest of the guns were shot at 741 and 965 yards. These were the conditions:

- 43°
- 870' elevation
- 85% humidity
- 5° incline shot angle

103gr .277
270/338 RUM improved
Muzzle velocity- 4140fps
BC .206

741 yards- 7.5 MOA up and hit the bottom half of the 8" gong on all three shots. Group was roughly 6"

117gr 7mm
284 Win specialty pistol
Muzzle velocity- 3045fps
BC .230

741 yards- 16.25 MOA All three shots hit the top half of the 8" gong. The group was about 4.5"
965 yards- 26.5 MOA All three shots were centered on the 1.5 MOA target rock.

117gr 7mm
7mm SAUM
Muzzle velocity- 3490fps
BC .230

741 yards- 3.3 MIL All three shots were centered on the 8" gong. The group was just under 4".
965 yards- 5.4 MIL All three shots were centered on the 1.5 MOA target rock.

200gr .338
338/375 Ruger specialty pistol
Muzzle velocity- 3015fps
BC .275

741 yards- 16.25 MOA All 3 shots were on the top half of the 8" gong. The group was about 5.5"
965 yards- 26.0 MOA All 3 shots were on the bottom half of the 1.5 MOA target rock.
 

Mark Dille

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Thanks for posting your testing results! Your work is always appreciated! So glad you were able to conduct terminal testing north of 4000 fps, almost 4100 fps! Insane! We would have not been able to come close to doing that here, and I really appreciate it!

 

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