The first 3 years of my development of my wildcats, one of the main points of interest was to see how far we could push the supersonic velocity limits, i.e. max range with 100% bullet stability before passing though the transonic stage of flight, which in my opinion is the end of true consistant and predictable bullet flight. Others may have different opinions on that, I am firm on mine from actual real world shooting and recording results, thats a different story however.
When we started with this long range thing we were testing two 338 Kahns that I made up on my heavy V-Block rifles. My rifle drove the 300 gr SMK to right at 2950 fps in a 34" barrel length and my brothers hit 3050 with a 36" barrel length.
In our testing we found that at our elevation, my Kahn was limited to a max supersonic range of 2380 to 2420 yards depending on the day and specific environmental conditions. This was tested by setting up a 20" round steel gong and starting at 2000 yards and then stepping back 50 yards at a time with a shooting platform on the back of my truck. We would shoot, confirm consistancy and then step back another 50 yards and repeat.
My brothers rifle with the slight edge in velocity would add another 75 yards on average to his max range.
What we found is that once we reached our max supersonic range, even 25 yards past that would result in catastophic stability lose. We were shooting in a freshly plowed field so it was easy to see impacts no matter where they landed and we always had two spotters and the shooter to spot shots. It was not hard to maintain 1 moa accuracy(in good shooting conditions) out to the super sonic limits of the rifles we were shooting at the time. BUT, even 25 yards past would result in groups tripling in size and at 100 yards past, groups would be measured in the 20-30 moa range!!!! At 200 yards past this point, it was very difficult to even predict where the bullets would impact.
This was the start of my 338 AM project. When the first prototype rifles were built we repeated this same test. This time however the two rifles, one an Xtreme Heavy Sporter with 33" barrel, the other Black Sunshine with 40" pipe.
My XHS, using TTI brass at that time had an average velocity if 3420 fps with the 300 gr SMK(glory days of good 408 brass!!!). We found on averge that the max range for that rifle was right around the 2820 yard range give or take 20 yards depending on the day.
Old Black Sunshine averaged 3510 fps with the same bullet and on average would produce consistant and predictable shot placement out to 2910 on average with the same variation from day to day.
Testing the much larger 338 AM we found that the higher RPM helped to some degree in stability as the bullet dropped out of supersonic velocity but not by much, perhaps adding 30 yards before things came completely unstable and unpredictable.
Richard Graves and I talked these results over and it was clear that with the right bullet, it may be possible to break the 3000 yard limit with super sonic velocity. Something that as far as I knew, had not been done to that point with a conventional shoulder fired rifle.
Richard ordered the dies and we waited.
In the mean time, TTI went belly up, or at least stopped offering brass to the public and we had to do the whole thing of finding suitable brass. In the end, the brass we came up with was similiar to the strength of Remington RUM brass. Good, but not TTI and it required max velocity to be dropped roughly 100 fps compared to the much stronger TTI brass. This set us back even farther trying to reach that 3000 yard range with supersonic velocity.
Even Black Sunshine was short by 200 yards with the brass we had to work with, at least with pressures were we could reuse the brass a few times.
Several months passed and a shipment of very aggressive looking aluminum tipped rebated boattail bullets showed up from Canada!!! These were needle point and to this day, the most aggressive design I have seen from any of the companies making aluminum tipped 338 bullets.
By this time, Black Sunshine had had its barrel set back 6" and rechambered so it no longer had the 40" pipe. I did still have my XHS with its 33" barrel length. Using Jamison brass, we loaded up the new 265 gr AT RBBT to what I considered max velocity with some pressure testing at the shop. The XHSs 33" pipe produced 3545 fps. Black Sunshine with its 34" barrel actually averaged less at 3530 fps because that bore had always been EXTREMELY tight compared to the lighter barrels from Lilja.
I decided to test my relatively lightweight XHS(18 lbs) to see how far she would go with this new super bullet.
We loaded ammo right there on the range. Started at 2600 yards and it took about a dozen rounds to get the drop figured for the new bullet. We had to use a BC of .880 to get the trajectory to match actual bullet flight. Still, that is a sizable increase over the SMK and also a significant velocity increased as well.
On paper, this combo should be able to reach out to around 3250-3300 yards with super sonic velocity so we stepped right back to 3000 yards(3010 to be exact). It took several shots to get on steel but we ran two, three shot strings at my 20" round gong and went 6 for 6 resulting in roughly a 3/4 moa group at +3000 yards, obviously maintaining supersonic velocity and stability.
We however could not move back any farther at this point and maintain a safe shooting condition because of the lay of the land.
We did however set up a couple weeks later at a location where we were at an even 3300 yards. That day however, we were unable to get a single bullet on target. Exbal was predicting that we should be able to reach this range but in reality, stability was non existant, groups, at least the impacts we spotted covered a 10 yard radius around the gong. Some shots were close, no hits and consistancy was nonexistant. As a side note, shooting conditions were about as ideal as you could have, slightly over cast, no wind, no mirage, 50 degree temps, dry ground, low humidity. If we could not reach it in these conditions, it would not happen.
To confirm the results, we returned to the 3010 yard range the next week. Conditions were far less then ideal and group size was much larger then the first time but we were able to put 7 for 12 shots on steel and all the misses were horizontal stringing showing consistant bullet trajectory again.
We had broken 3000 yards but just barely and we had no location where we could test the distances between 3010 and 3300 yards. I would imagine the max range would be in the 3100 to 3150 yard range judging from the results at 3300 yards and what we had seen with the lesser chamberings and how their consistancy degraded at their limits.
About a year after that, I came out with my 338 Allen Xpress, most know its just another version of the 338 Lapua Improved but not so aggressive in shoulder diameter, same as my other AMs and AX chamberings.
This chambering was able to get the 300 gr SMK to 3000 fps in 30" barrel lengths and obviously roughly matched the velocity of the two Kahns used in the first max range test.
I did do some testing with the 265 gr AT RBBT prototypes and was able to get them to an even 3200 fps. Interestingly enough, when checking actual bullet drop, it was less then that produced by the much larger 338 AM. By that I mean I had to use a higher BC value to get actual bullet trajectory to match up with computer predicted trajectory. I am not saying the 338 Lapua Improved will shoot flatter then the 338 AM so lets make that clear.
BUT, the BC I had to use was 0.920 with the 338 AX and 0.880 for the 338 AM at much higher velocities. I have no doubt this is simply because of the extremely high rpms created by the 338 AMs +3500 fps velocity and it took much longer for the bullet to "go to sleep" after release from the muzzle.
Xbal was predicting that the 338 AX would be able to reach 3000 to 3050 yards with supersonic velocity. After seeing what the 338 AM did and how it did not reach the limits of what xbal predicted I was expecting to see about 150 to 200 yards less reach and thats just about exactly what we saw. It was not hard at all to hold 1 moa out to 2800-2850 yards but anything past that, consistancy dropped dramatically. At 3000 yards, nothing resembling consistancy could be managed and we tried on several different days. Still, 2800 yards is not to **** bad for this class of chambering.
Just for the hell of it, I decided to try my heavy rifle in 7mm AM. Shawn knows which rifle that is as I took to Idaho and hunted whitetail with him using that rifle connecting on a beauty at 850 yards.
I wanted to see how this wildcat would compare using the 200 gr ULD RBBT loaded to just a hair short of 3300 fps. The BC of this bullet has always been right around .920, at least I have to use that to match xbal up with actual bullet drop.
Again, Xbal would predict a max supersonic range of around 3150 yards. We did not reach that. Testing this rifle was quite frustrating because it was difficult to see actual bullet impact location even with several spotters. We did manage to get on steel at 2900 yards on day and the rifle held close to 1 moa but it was so difficult getting on target by seeing the impact that we really never did know if we were hitting steel or not. If there was any breeze at all from behind us, we could not hear the gong. IN fact on several days we would have to drive up just to look at the gong or around the gong to see if we could get an idea of where the bullets were landing.
In many cases, the groups fired were quite good, it was just very difficult to see your impacts well enough to adjust your optics to get on steel.
In the end, it was determined that the 7mm AM in a heavy rifle that could reach near 3300 fps with this bullet would reach out to 2900 yards at our elevation with consistancy. Seeing the bullets impact in many situations however would be nearly impossible.
For all of this testing, we used two scopes, both NF NXS 5.5-22x50mm. One with the NP-R2 reticle on earlier tests and then the NP-R1 on latter tests, and all on 40 moa rails. No these scopes would not dial up to a 3000 yard zero but they had enough vertical adjustment and enough reticle holdover range that we were able to get on target topping out the scope and then using the reticle for holdover.
I was always amazed to see how the point of impact would change from day to day. At 800 to 1000 yards, point of impact would stay extremely reliable, seldom more then 1/2 moa from day to day even with different shooting conditions. But at ranges past 2500 yards, it could be DRAMATICALLY different needing to adjust by several moa from day to day.
This was likely due to updrafts and downdrafts that simply can not be predicted accurately at these ranges, at least not by me!!! In my opinion, even with a rifle capable of consistant stability out to 3000 yards, its still a shoot and adjust type of deal. Until you test that first bullets flight, no matter how dead on you think you are, you never know until you let one fly and prove the conditions at that range.
Those are my results. Its been a couple years since I tested out to 3000 yards.
I remember reading on one of the Varmint Hunters magazine last summer I believe where Gordy Gritters wrote an article about consistant groups at 2800 yards and more using a 338 with 300 gr SMKs with nearly identical performance to my AX, even slightly less. He was at lower elevation then I was so I sent him a few e-mails asking for more details on his results.
He made several dogdes to slip the questions but I presisted and finally said from what we have found, his results were impossible and that he needed to clearify his findings.
Finally, he admitted that he had only been out one time shooting at this range and that while a few of their shots hit the target they were shooting at, the vast majority of shots never game close but they figured that was simply do to wind conditions. I told him he was several hundred yards past his supersonic limits and that was the reason, not conditions and that he needed to do more testing and print a retraction on his article stating that he did not do enough real world testing to prove his theory that if you had enough adjustment in your scope, anyone could reach out to 2800 yards with consistant grouping with a quality rifle. He actually wrote this in his article.
HE got pretty puffed up at me at this point and started discrediting my results so I called the Varmint Hunters editor and told them who I was, what I do for a living and how they are discrediting their name by printing articles like this and misleading new shooters with bad information.
That was the last article Gritters wrote for varmint hunters about long range shooting!!!
My point for bringing up this story is simple, anyone can say they have shot at extreme range, many probably have but putting a couple shots on or close to your point of aim is not consistancy and its easy to print part of the story which does nothing to educate the readers. Be wary of those that claim its possible to reach out past 2500 yards with conventional performance chamberings, 99 out of 100 times, they have no idea what their talking about.