Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
http://www.youtube.com/watch?v=u4yfajXoiqg
Since there was a fair bit of debate on my LR fun shoot post, I thought I would just make a thread so that any debate could continue without cluttering up that thread.
Here is the task. This spring Troutseeker and I are going to push our 223's and see if it can reach the mile accurately.
I will be using a Pac Nor 7 twist 5R 28" match barrel on a Stevens 200 action to direct 75gr and 80g Amax, and 80gr Bergers. This is a new barrel but initial testing today shows it has potential. Got some 1/4" groups at 100yds.
TS will be using 75gr Amax in a Savage 12FVSS. The rifle is brand new and unfired.
In case you haven't heard, there is much talk about bullets loosing accuracy after they go subsonic. It is repeated so often that it has become an urban legend.
Having shot almost to 2000yds, I have seen many bullets happily fly accurately after becoming subsonic. Some bullets don't make it though.
I have also seen how accurate cast bullet black powder cartridge rifles can be. These operate almost always in the subsonic region and have very low BC numbers. 600 and 800yds groups have broken MOA accuracy. Amazing considering these are with period rifles (modern construction) and sights. Test by the US army in the 1800's pushed 45-70 slugs to almost 2 miles and they actual recovered the bullets in a rather large target.
The key to this legend are bullets like the 168gr MK that are supposed to loose stability and tumble once they slow down (personally not use them so can't say). Another surprising bullet is the 175gr MK out of a 308. Hit the wall at 1400+yds. Was spotting and it was quite neat to watch.
One of the key factors debated is whether the bullet simply isn't spinning fast enough, hits the transonic turbulence, wobbles which leads to tumbling. Or something us non aero eng know about.
Having shot some 155gr Amax with 12 and 13twist barrels well beyond where it would go subsonic, I can say, spin stability is not always the key reason. But I am sure for some bullets, it plays a very important role.
The detractors believe that a bullet so small and light as these 22cal bullets would just get tossed around by any wind and loose all semblance of accuracy. This is if they don't first tumble after they go subsonic.
Wind is indeed a big problem but I suspect that it will be no worse then driving a 308- that's what the number predict.
I have shot the 75gr Amax at moderate speeds to 1200+yds. Definitely subsonic and in the winds of the day, accuracy was indeed nothing special. However, the bullet did get there.
My first Pac Nor had no issue putting these 75gr bullets into 1/2 to 2/3min at 1000m. Another novice shooter hit the same target that day so no fluke. At this distance, the bullet should be right in the transonic speed range and that is not ideal so the theory goes.
In order to see what happens that far out, I must first make sure the bullets DO stay stable after being subsonic. This means shooting to out to 1400yds. Accuracy would need to be in the 1 to 2 MOA range under calm or driveable conditions or else you are pretty much spraying the hillside. Lots of properly sized rocks in my target area so this will be easy to set up.
If that works out, then to continue to push further until we get to or not get to a mile (1760yds).
It will take ALOT of scope elevation and at some point, holdover will be necessary. Spotting the impacts will be challenging but the ground is quite dusty so I hope to get some kick up.
I will post my results as I go so that we can see how successful this concept is. Wind will be a huge problem but that is the same even with a 338. I will try for calmer weather.
I am very optimistic my pipe can make it happen. The faster 7 twist will certainly give the 80gr bullets all the spin they will need. The accuracy shown so far gives me the mechanical accuracy needed. Now to see how the bullets feel about making the trip.
Will also compare the relative drops of the Amax and Berger (if the pipe likes the Bergers). They are almost identical in shape. One with a poly tip, the other HP. Will be interesting to see which drops more. Any bets on which one?
Jerry
Since there was a fair bit of debate on my LR fun shoot post, I thought I would just make a thread so that any debate could continue without cluttering up that thread.
Here is the task. This spring Troutseeker and I are going to push our 223's and see if it can reach the mile accurately.
I will be using a Pac Nor 7 twist 5R 28" match barrel on a Stevens 200 action to direct 75gr and 80g Amax, and 80gr Bergers. This is a new barrel but initial testing today shows it has potential. Got some 1/4" groups at 100yds.
TS will be using 75gr Amax in a Savage 12FVSS. The rifle is brand new and unfired.
In case you haven't heard, there is much talk about bullets loosing accuracy after they go subsonic. It is repeated so often that it has become an urban legend.
Having shot almost to 2000yds, I have seen many bullets happily fly accurately after becoming subsonic. Some bullets don't make it though.
I have also seen how accurate cast bullet black powder cartridge rifles can be. These operate almost always in the subsonic region and have very low BC numbers. 600 and 800yds groups have broken MOA accuracy. Amazing considering these are with period rifles (modern construction) and sights. Test by the US army in the 1800's pushed 45-70 slugs to almost 2 miles and they actual recovered the bullets in a rather large target.
The key to this legend are bullets like the 168gr MK that are supposed to loose stability and tumble once they slow down (personally not use them so can't say). Another surprising bullet is the 175gr MK out of a 308. Hit the wall at 1400+yds. Was spotting and it was quite neat to watch.
One of the key factors debated is whether the bullet simply isn't spinning fast enough, hits the transonic turbulence, wobbles which leads to tumbling. Or something us non aero eng know about.
Having shot some 155gr Amax with 12 and 13twist barrels well beyond where it would go subsonic, I can say, spin stability is not always the key reason. But I am sure for some bullets, it plays a very important role.
The detractors believe that a bullet so small and light as these 22cal bullets would just get tossed around by any wind and loose all semblance of accuracy. This is if they don't first tumble after they go subsonic.
Wind is indeed a big problem but I suspect that it will be no worse then driving a 308- that's what the number predict.
I have shot the 75gr Amax at moderate speeds to 1200+yds. Definitely subsonic and in the winds of the day, accuracy was indeed nothing special. However, the bullet did get there.
My first Pac Nor had no issue putting these 75gr bullets into 1/2 to 2/3min at 1000m. Another novice shooter hit the same target that day so no fluke. At this distance, the bullet should be right in the transonic speed range and that is not ideal so the theory goes.
In order to see what happens that far out, I must first make sure the bullets DO stay stable after being subsonic. This means shooting to out to 1400yds. Accuracy would need to be in the 1 to 2 MOA range under calm or driveable conditions or else you are pretty much spraying the hillside. Lots of properly sized rocks in my target area so this will be easy to set up.
If that works out, then to continue to push further until we get to or not get to a mile (1760yds).
It will take ALOT of scope elevation and at some point, holdover will be necessary. Spotting the impacts will be challenging but the ground is quite dusty so I hope to get some kick up.
I will post my results as I go so that we can see how successful this concept is. Wind will be a huge problem but that is the same even with a 338. I will try for calmer weather.
I am very optimistic my pipe can make it happen. The faster 7 twist will certainly give the 80gr bullets all the spin they will need. The accuracy shown so far gives me the mechanical accuracy needed. Now to see how the bullets feel about making the trip.
Will also compare the relative drops of the Amax and Berger (if the pipe likes the Bergers). They are almost identical in shape. One with a poly tip, the other HP. Will be interesting to see which drops more. Any bets on which one?
Jerry
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