EXTREME .308 "Whiteout and Alpha 30 wins 1st & 2nd at EBR 200 yd event!

[C.ALLS]

When will some test results be posted using air only?

I'll get some results up ASAP.  What are you wanting in a rifle?

[ancient1one]

1st place is a big accomplishment in a field 14. 1st and 2nd is outstanding. Congratulations to everyone involved. 

[jimreed1948]

When will some test results be posted using air only?

I'll get some results up ASAP.  What are you wanting in a rifle?

.257 or .308

200-250 yards

I like accuracy.  I don't hunt any more.

[dyotat100]

I decided to login and tell my side.

It was a pleasure to hang out with Mike and Chris. Really nice guys and there guns looked and shot real nice. But after seeing how they group I don't think it was the right setup. I'm not knocking there guns its just the way they shoot 2-3 good shots and then the next is 4-6" off. They are great hunting gun. I'm sure the thin barrel is a factor and not sure if the barrel band has a part in it also. I think the bullet was just to big. I shot a 112 gr accurate mold bullet at 3200 psi with no wind correction at 1000 fps

I planned on shooting .257 in the 200 yd event. After 2 days of shooting in there wind I decided to pull the scope off of my .25. It is a 10-50x60 sightron. The problem was I couldn't see where I was hitting the paper most of the time with the 6-24×56 hawke. So after messing with it Saturday before and after I shot in the extreme 75 yd event I was frustrated and pulled my regular setup. I then started shooting off my old tank to see what was going to work. Then they kicked us out because the range closed.

So now I'm at a loss as to what to do. So I decide to shoot the .308. I take it in the room and clean the barrel. I sized half the bullets I had for me and Tom sized the half he was going to use if he shot his .308.

So we plan to go to the range before they open and sight in at the rifle range. Tom with his .357 and me with my .308.

I take a shot at the 200 yd berm to see where it was at and it was a  little high. Made a adjustment and shot again. It was right where I aimed. So I shoot 4 shots on the target that Tom had set out and it grouped good enough not to shoot anymore.

So I have taken 6 shots with my .308 before the event. So I was in the first relay. I decided to fill after every shot because I don't have it setup to shoot a curve. 

Match starts and I take 2 shots a the sighter target and there both in the black. I move up and start shooting the lower right target. I take 5 shots I think. I look and can't find all 5 shots. I decide to move on to the next target. So I shoot out the next target. Well somewhere in the shooting I had a partial shot. Anyone that has a airforce and has not closed the breech all the way knows what I'm talking about. It is like a half shot and falls way short.

So I go on and finish my shooting. I then take a look back at 1st target and can see 5 shots now. So I'm done. I shot my .308 a total of 31 shots 6 before and 25 in the event. If I would have spent the time I did with the .257 who know what would have happened.

After thinking about it for awhile the only thing I can figure is the partial shot dropped into the lower target giving me a 6th shot on it.

So not closing the breech cost me 20 points and I lost by 5.

I learned a lot. Defiantly not to shoot the bottom targets first. I also made the finals in the 75 yd extreme which was 100 yd final. Winds were so bad that you would hit the target next to the one you were aiming at. I ended up finishing 15th in the final. I was happy to make the final.

I'm hoping I made 2 new friends and would like to keep in contact. I won't give it away next year I tell you that right now. I will be way more prepared with a spotting scope also.

[Rizen 1]

Doug, it was awesome meeting you! We are still on the road.... 6 more hours . You have definitely made 2 new friends. Competition is one thing... Friendships are another. I would never let the frustrations of competition ruin a friendship. You definitely would have won if it were not for the deduction... I apologize if we offended you in any way. We worked so hard and there were Alot of people involved in our build, we got so excited that we placed that I let it overshadow everything else.  We had issues also.... Only having 24 power scopes and not being able to see the holes was only one of the issues....We have shot  2 inch groups with our guns and we have shot 10 inch groups. After initial testing, Bob thought the bullet was a little to long... Kip confirmed that by showing us on our targets that the bullet was yawing. We fought bad leading of the barrel and ran out of time for testing, but decided to come give it a shot anyway. Right before the 200 yd shoot Chris shot the best  5 shot group ever at 2.1 inches, then we shoot in the competition and they are 2-3 touching and the other 2-3 out of the Black.... I think we are close to the right set up, but definitely need to make some adjustments. It was an honor getting to shoot with you and we look forward to next year.

[rsterne]

It sounds like the event was pretty typical for an important contest.... last minute changes that you always wonder about, or just plain running out of time to prepare.... and the inevitable lady luck smiling or frowning as the case may be.... The friendships made, however, are far more important, and last long after the event is forgotten.... My congratulations to all three of you....

I received some samples of the Whiteout bullet tonight, along with some great T-shirts, complements of Mike.... thanks so much for those.... I measured the bullets, and they are 1/16" longer than the design I gave Veral.... The Meplat is slightly smaller as well, but that doesn't concern me as much as the overall length.... That is the most critical dimension for bullet stability, and with the Whiteout printing 5 shots touching, consistently, at 100 yards.... but being inconsistent at 200 yards.... and showing evidence of the bullets yawing in the target.... we certainly know where to look to improve the consistency.... Pushing the Meplat back to the original length by installing a 1/8" diameter HP pin to increase the diameter should make the bullet shoot at 200 yards and beyond as good as it does at 100....

So much for the coulda-woulda-shoulda....  .... I have feeling that Chris, Mike, Doug, and Tom (and probably others) will all be there again next year.... with properly sorted equipment and wayyyyyyyyyyyy more experience.... Our little group from the GTA (and I take pride in being involved, even if I didn't get to shoot) has made its mark.... and I see great things in the future....

Bob

[Extreme Big Bore]

I have been a professional snowmobile racer for the last 18 years and have come up with a formula for success for any competition. preparation + proper performance + %10 luck = success take out any of the three and it usually will notwork out for you great shooting by all but at the end of the day it is what it is.

Brent Hoag

[bluethunder]

I too have a custom built .308 Extreme. Mine has a 32" Shilen  match grade 1 in 10" twist stainless steel barrel with an outside diameter of .800" inches. Most of my shooting is at my home range, Tri-County Sportsman Club.  It's a 300 yard range. I don't believe in 3 shot groups. Anyone can get lucky from time to time and shoot a screamer. I do all of my testing with 10 shot groups. My best 300 yd. 10 shot group is a 5.1" group. Velocities are 830 fps with a 183 gr. bullet and 910 fps with a 153 gr. bullet on "air" regulated to 3800 fps. So those of you wondering what the Extreme velocities would be on air,  here is a base line to compare to. Neither bullet has shown any tendency to yaw on target even out to 700 yards. The bullets are the RCBS 180 gr. and 165 gr. Silhouette bullet. If I would have the rifle rebuilt a 3rd time, I probably would have the chamber specified to be no larger than .3095" As it is, the chamber is .3104" and I have to shoot .3103" bullets for maximum accuracy. The bullets are probably being swaged down on entry to the barrel, but if the bullet enters the barrel crooked from a loose chamber your accuracy is all ready down the drain. .309" bullets routinely get beat by the .3103" bullets. And .308" bullets shoot down right bad. What was the barrel twist in the rifle shooting the Whiteout bullets. Just from the look of them I would guess a 1in 8" twist would the minimum required.
      What I'd really like to know is what B.C. you're getting out of that Whiteout bullet. I took my bullets and shot them over the chronograph at 1" foot from the muzzle. Then I set my chronograph and CAREFULLY shot over the chronograph at 100 yards. Then I took the velocity loss calculation and entered it into the JBM Ballistics Program for a ballistic coefficient. My best bullet only performed at a B.C. of .250. That means that with a 10 mph crosswind at 200 yards my bullet will be pushed a match losing 7.5". So in my humble opinion, a bullet--which is accurate and creates an improvement in B.C. is an improvement in the right direction.
       Helium is a good way to game a match-- but for normal shooting, I don't want to deal with the hassle and cost of using an exotic gas. If the match directors want to create an "Unlimited Division" then go for it. But the regular shooter should not be pushed into such exotic and expensive measures to be competitive. I'm all for eliminating Helium for the regular match competitor, but for the continuing scientific push to take air rifles to the limit of their capabilities, create an unlimited/experimental division.

[K.O.]

well in the design thread it was estimated and I will look to find it... I do remember it was basically very close to that of the Lapua 200g subsonic...

http://www.midwayusa.com/product/381996/lapua-subsonic-bullets-30-caliber-308-diameter-200-grain-full-metal-jacket-boat-tail-box-of-100

now if you want what it really does then Lapua uses Doppler to get their figures...

http://www.lapua.com/en/products/reloading/bullets/centerfire-rifle-bullets/15

[rsterne]

Chris used the drop from a 75 yard sight in to a 200 yard target (46") to estimate the BC at ~0.475.... He plans downrange Chrony tests soon....

Bob

[K.O.]

found the initial estimate...

"
The JBM Ballistics Calculator says that over that velocity range the G1 BC is a staggering 0.80-0.855.... I think a fairer measure would be to use the G7 (boattail) standard, where the BC over that velocity range is 0.351-0.367....
"

http://www.gatewaytoairguns.org/GTA/index.php?topic=93646.0

[Rizen 1]

Chris found a source for 2500 psi helium tanks for around $125.00 per tank. They are standard tanks used for filling balloons... Running it through his shoebox compressor to fill our omega tanks, we get 3 full 4500 psi omega tanks from that one 2500 psi tank.  With our booster setup, we then get 350-400 shots from 1 of those omega tanks. So we get about 1200 shots on that one $125.00 tank.....  which is about $.10 cents a shot.......   Depending on where and how you get your air, if You have the right setup, Helium can be as cost effective as air if not more so....PRODUCING ALMOST TWICE THE POWER, enabling us to experiment with taking airgunning to the next level.

Here are a few more pics...

[rsterne]

Hmmmmmmmmmm.... about 10 cents a shot, at 400 FPE each?.... It costs about 2 cents a shot for CO2 in a gun that only puts out 7 FPE (2240).... Yeah, but air is free, right?.... Not if you fill your tanks commercially it's not (and you aren't going to hand pump to 4500 psi)....

Bob

[C.ALLS]

I know that after the last 3 months of experimenting with Helium I will never be without a tank in my garage. I suggest anyone wanting more power from their bigbore give it a try.

[C.ALLS]

It's a 300 yard range. I don't believe in 3 shot groups. Anyone can get lucky from time to time and shoot a screamer. I do all of my testing with 10 shot groups. My best 300 yd. 10 shot group is a 5.1" group. Velocities are 830 fps with a 183 gr. bullet and 910 fps with a 153 gr. bullet on "air" regulated to 3800 fps. So those of you wondering what the Extreme velocities would be on air,  here is a base line to compare to.

Have you tuned the gun for a 3800 psi fill?

[bluethunder]

The only thing that I have done to the .30 cal Extreme in the way of tuning it to cut about 1 1/4 coils off of the stock hammer spring. I regulate at 3800 psi. and Brent sets the guns up for 4500 psi. I get about 40 shots per 90 cu. ft. bottle when regulating at 3800 psi. with the cut hammer spring. Cutting the hammer spring also reduced my extreme spreads. From time to time I'll shoot an entire session over the chronograph. Before I cut the spring it would not be uncommon to have a 15 fps. extreme spread in a 10 shot string of fire. By cutting the spring, air consumption improved and my extreme spreads for a 10 shot string tend to average about 7 fps.

[rsterne]

In the mid 900s with a 153 gr. bullet is just about where I would like to see a .308 using air for the next EBR.... or drop the caliber to .257 and the bullet weight to just over 100 gr. at the same speed...

Bob

[C.ALLS]

The only thing that I have done to the .30 cal Extreme in the way of tuning it to cut about 1 1/4 coils off of the stock hammer spring. I regulate at 3800 psi. and Brent sets the guns up for 4500 psi. I get about 40 shots per 90 cu. ft. bottle when regulating at 3800 psi. with the cut hammer spring. Cutting the hammer spring also reduced my extreme spreads. From time to time I'll shoot an entire session over the chronograph. Before I cut the spring it would not be uncommon to have a 15 fps. extreme spread in a 10 shot string of fire. By cutting the spring, air consumption improved and my extreme spreads for a 10 shot string tend to average about 7 fps.

Brent does set his guns up for a 4500psi fill but his springs don't get into a bell curve till around 4800-5000psi. You really should spend the time to find an appropriate spring for your fill range. I tuned our guns and set them up to be filled to the sweet spot between shots. We can be 100-150psi off in either direction and the guns will still be well under %1ES from shot to shot. I bet you would get way more shots from your tank once the gun is not wasting so much air.

Another thing we've been experimenting with is lock time. The Extreme guns have a little over a 2 " hammer travel after the trigger is pulled to when the valve is hit and opened. That's a good bit of time for things to change before the bullet gets out of the barrel. The Whiteout hammer travels 1.6" and just the small change made the gun shoot better IMO. I'll be trying a 1.25" hammer travel soon and I believe that will be even better.

[bluethunder]

To be honest I really have not been concerned about even having a bell curve. I always shoot tethered and regulated. I had the rifle built as an experimental test bed for long range air rifle shooting. It was never going to be used for hunting. So long as I get a reasonable number of shots out of a tank (40 shots- and I have more than 1 tank) and really low extreme spreads I'm happy. Your extreme spreads of 1% on 1,000 fps would be 10 fps. My extreme spread average in a 10 shot string is only 7 fps. So I'm doing all right in that category. Because I'm using air, if I'm a little inefficient it doesn't cost me anything.
        If I were to get into Helium I'd be more concerned with efficiency. And you have picked my interest in the use of Helium. But getting into Helium runs contrary to the very reason that I got into air rifles in the first place and that is they're cheap to shoot. If I drive up my air rifle shooting cost to where shooting firearms becomes cheaper--to me--I've lost sight of my goals. I am much more interested in taking your research and modifying it to maximize what an "air" powered rifle can do. I'm thinking using the Whiteout concept of a bullet shape at about 160-170 grains. Something that would work with my 1 in 10" inch twist air powered rifle. I'm thinking that a good profile for the bullet would be to take a Berger Hybrid bullet of about 160-170 grains, then cut that chunk out of the middle bore riding area so that you end up with the front and rear driving bands similar to the Whiteout.
   The lock time issue is huge on our air rifles. They are more like shooting flintlocks--pssst wait bang! I had a heavy flat bottomed "F" class stock fitted to my Extreme to help stabilize it off of the benchrest. I even shoot the rifle different than any of my firearms in that my left arm solidly holds the flat bottom of the stock down against the front benchrest. Of course the rear of the rifle is on the sandbag. The Bald Eagle benchrest has the adjustments for up and down & right and left built into it so that frees both arms for stability and follow through. So yes, I am interested in reducing the lock time on the Extreme. If your test workout on the  1 1/4" hammer I'd be interested in obtaining one. How would I go about that?
    What twist rate are you using on your Extreme? You mentioned you were experiencing some bullet instability, are you going to shorten the bullet or increase the twist rate?    Stew

[C.ALLS]

I understand that you're happy with your ES but what I think you're missing is that a better suited spring for a 3800psi fill will give you your same results with a less violent hammer to valve hit. When a hammer spring and valve are inside their sweet spot the relationship is much easier on the pair and less violent which results in a smoother shot cycle and a gun that's easier to shoot accurately IMO. You could continue to modify your stock spring but every time you shorten that spring by removing coils you're actually making it a stiffer spring rate and what I think you'll find is that in order to get that spring to operate in a 3800psi sweet spot you'll end up with a negative preload situation which doesn't work well with these rifles.

The shorter lock time hammers are available through Brent but they're in the testing stages and I suggest you wait till I figure out the best combination before ordering one. Also we're using a 1:8" twist barrel and the Whiteout bullet as designed would've stabilized perfectly but the mold maker decided to build the bullet mold about 1/16" longer than specified so......