300 gr SMKs consistancy dropping out of Supersonic velocity...

[edge]

I thought a year or two ago GG was attempting to shoot some chucks and the groups opened up quite a bit just after subsonic. Of course it may not have been GG and then perhaps it was not a .338 ......a mind is a terrible thing to waste

edge.

 

[jwp475]

I thought a year or two ago GG was attempting to shoot some chucks and the groups opened up quite a bit just after subsonic. Of course it may not have been GG and then perhaps it was not a .338 ......a mind is a terrible thing to waste

edge.

Yes gg shot a few of the little underground varmints with a 338 Laupa

 

[ss7mm]

From the VHA site:

Gordy Gritters
Life Member

Posts: 5
Date: Apr 17 9:47 AM, 2008
Views: 325

Flybuster wrote:
Hello Gordy, I have a few questions for you. What Caliber and Cartridge are you using at 2 miles? How big would your groups be at that distance? How much wind drift is encountered with say a 5 mile an hour wind? How many hits does it usually take you to hit a prarie dog at that distance?
And finally how many prarie dogs have you actually killed at these distances? Thanks for your response, quite interesting.

​

Hello, Flybuster

Sorry I didn't see your question posted here earlier - I'm busy enough in my shop I don't get on forums very often.

I am just finishing up my Two Mile Shooting article for Varmint Hunter - it should be in one of the upcoming issues soon. I'll answer your questions here, and I'll have a whole bunch more info in the article - so keep your subscription current so you don't miss it!!!!!

We're using a blown out 338 Lapua Magnum I designed specifically for this project (I call it the 340 Gordy Supermag - just as well have a little fun with it, huh?). It shoots the 300 grain Sierra Matchkings at 3000+ fps. The wind drift for a 5 mph wind at 2 miles is around 30 feet (close to 10 moa on your scope's windage knob).

I'll let you wait until the article comes out to see if we ever have actually hit anything at that distance, and if we have hit anything, whether or not it was a confirmed kill. But I will tell you that one very young dog we shot at just wouldn't go down his hole, so we shot at him 22 times in just a few minutes. We then drove our 4-wheeler out there to see if he was laying there. We hit the mound with 16 out of the 22 shots, the "group" on the mound for those 16 shots measured right about 18", and the whole 22 shot group measured right at 36". It had just rained a little a couple days before and it was very easy to see exactly where all the shots hit.

That obviously was a very good day for conditions (quite windy, but very steady) - one other time the wind was switchy and we had a hard time keeping the shots within 20 feet of the mound. Most days though we could hit the mound quite regularly.

So thanks for your interest and keep your eyes open for my upcoming article.

Thanks!
Gordy

 

[MagMan]

interesting.....

 

[Shawn Carlock]

Kirby,

Sorry I did not get on this earlier. JR and I shot the Edge's with 300 SMK's alot last year out to 2000 yards. Our standard muzzle velocity 2818 fps. Our Exbal calculated transonic zone was at 1900-1950 fps. Shooting at 1694, 1814, and 2008 yards followed what you have stated. out to 1800 and some change very happy with shooting in the given conditions 3 shot groups 10-15 inches. At 2K couldn't hit my *** with either hand 4-6 feet. I managed one almost dead center hit on the 18"plate but took 6 shots and 5 feet of group to do it. I'd chalk the 2K hit mostly to luck. Out to 1800 I don't think you would want to bet against it. I plan to shoot these distances again pretty soon on video for the up coming "Greatest Hits" video this winter. I'll let you know how it pans out but I suspect it will be about the same.

 

[jwp475]

A 36" group at 2 miles is around 0.98 MOA I think that the flag must be raised

 

[Fiftydriver]

Shawn,

We talked about this a couple years back when I was working with the 338 Kahns. My initial load was in the 2900 fps range and my results were exactly what you were seeing with your Edge, within 100 yards or so as far as max range was concerned.

We also discussed this concerning the 308 and how its consistancy really dropped once it dropped below super sonic velocity.

I would agree with you also that at times, it can appear that you can make reliable hits at ranges past your super sonic limits. I recall the first shot I took with my 338 Kahn at around 2200 yards and it dead centered the target rock I was aiming at. I was very excited about that performance until I took the second shot and I was not within several feet of the target rock. It only went down hill from there with some of the impacts not even visible to me or my two spotters.

I know with the 338 AM it has been the same way, occasionally with the 300 gr SMK, you can reach past its super sonic limits but they are few and far between as far as consistancy goes and it seems like there is a wall that is around 40-50 yards thick that if you shoot at ranges closer then that wall, great results, past that wall, its totally random.

I did get a reply from Gordy and to his credit he did not personally attach me because I questioned him on the article. Below is his reply to my questioning:

Hi, Kirby

I don't mind at all your questioning this. We don't have extensive experience with this, but we have gone out to SoDak doing this about 15 times or so, all in the same place. The 1/2 moa is not a common occurrence, but we've had a number of days where we could hit the mound we're shooting at very regularly. That day we could do no wrong, but some other days we can't keep it even close. But the one time I talked about where we hit the mound 16 times out of 22 shots was an exceptionally good day condition-wise - definitely the best day we ever had for this. I'm going to guess we've had it over half a dozen times when we've been able to keep them close to 1 moa for the majority of the shots, though, and were really surprised by this at first, but we've done it often enough now that we aren't so surprised by it any more.

I know I really questioned it also when I read about Bruce Artus and Kregg Slack doing this at 3125 yards, and still did after talking on the phone to Artus. They sent me a video that they took and that is what gave me the idea to video our efforts. We just used a fairly high quality video camcorder that had enough magnification to zoom in to where we could easily see the gong from the firing line and the puffs of dust at the gong when the bullet got there - definitely not high-def, but sure shows it good enough to easily see what's happening.

We also wondered about the bullets staying stable since we figured they were going sub-sonic around 2200 yards or so, and we have talked about setting one of our 1000 yard targets up at 3600 yards to see if they go through the paper point-on or sideways, but have not done that yet. We often see guys trying to shoot 168 Sierras out of 308 Win's at our 1000 yard matches, and they will almost always be tumbling by the time they get there, but will still often be grouping quite well - often under 10 inches (kinda hard to measure center to center with keyholed bullet holes though!!

So I don't know what to tell you, other than what we've seen and done for ourselves enough times now to have a pretty good feel for what's happening for us - but it sure is intriguing though, isn't it

Thanks!
Gordy

He does not attack me but also does not offer any meaningful explination how he is getting these results and others can not. I have seen some of the rough video from Artus and Slack and from the video I saw, it was far less then convincing. In fact, the results they were getting appeared to be no more consistant then what we are seeing. That said, they happened to get a couple shots on steel and somehow got lucky enough to have a bullet land on a P-Dog at 3125 yards. The skill level on that shot I would rate at around 1% and 99% luck.

I also find it interesting that they are getting moa groups with the 308 win at 1000 yard matches when the bullet has been proven to be tumbling??????

Magic is happening down there I tell ya. Hell, the 7mm AM would be a 4000 yard rifle in that mystical part of S. Dakota!!!! lets go whitetail hunting!!!!

 

[edge]

You tweaked my memory, I thought that I was remembering the MOAG stories, but it was your Kahn story all along

http://www.longrangehunting.com/forums/f17/338-allen-magnums-first-chuck-hunt-bit-success-16968/

edge.

 

[Fiftydriver]

**** does that seem like a long time ago that that happened. Made me sit back and think about what has happened in the last 2 years!!!!

Wow.

I need to get my rear out and get that 2500 yard hit this summer yet!!!

 

[BountyHunter]

It is not uncommon in the 1k BR matches to see the 168 SMKs tumble at 1000 and still hold MOA. Having said that it is not uncommon to see them 20 inches either.

As for the Slack gun, I bought the their first 338 Lapua improved that you see in the pics in their article. I used it as a LR hunting gun for about 4 yrs before selling it. I only shot it at 1k matches once. Had to take the brake off to shoot in the HG class and the recoil would bring it up off the front bag each shot. Shot a 10 shot group of 7" and 8" that day which under the circumstances was pretty good. The gun certainly would shoot.

I know Gordy Gritters and as he says it might have been a fluke with exceptional conditions. However, I certainly would not question his integrity which now seems to be the continous practice of some here questioning all other smiths that are not favored members here.

Now that certainly calls for raising the BS flag!

BH

 

[J E Custom]

I'm not to old to learn something so anyone feel free to chime in.

My under standing of this phenomenon is that it is when the bullet
passes through the sound barrier that things go bad .Not from then on.

Some of the guys that shoot subsonic rounds get very good accuracy
at subsonic velocities.

So any projectile is affected by this phenomenon no mater what it weighs.

J E CUSTOM

 

[edge]

SNIP

Some of the guys that shoot subsonic rounds get very good accuracy
at subsonic velocities.

So any projectile is affected by this phenomenon no mater what it weighs.

J E CUSTOM

Wouldn't a subsonic round be fairly short range?

Even a 1.0 B.C. bullet shot at 1100 fps would fall like a rock!

edge.

 

[gamedog]

Is it 1129 fps when the bullet comes out of supersonic?

 

[J E Custom]

Wouldn't a subsonic round be fairly short range?

Even a 1.0 B.C. bullet shot at 1100 fps would fall like a rock!

edge.

Yes but the point was that if you started a bullet at 1100 ft/sec and it was
stable it would remain stable for it's practial range depending on its weight.

And the heavy'er the bullet the longer it would retain it's velocity (Just like the
300gr SMK compaired to a 150gr SMK shot at the same velocity).

My understanding was that the projectile would lose it's stability while passing
through the transonic speed,and can't regain accuracy once through .

The reason the new tank rounds are fired out of a smooth bore and the projectile
has stablizing fins is to avoid this problem, and eliminating the yaw that occurs
when passing through the sound barrer with a rifled barrel and a rotating projectile.

So once the bullets path is disrupted it cant find its way back on track. Hence the
accuracy problem beyond the transition.

J E CUSTOM