I was able to run up with my wife this past long weekend and spend some time with my good friend Richard Graves and his family. The idea for the weekend was just a few days to get away but we also wanted to play with his 277 Allen Mag and a new bullet Richard had made up for testing.
Initially when starting the 270 Allen Mag project quite a while back, Richard had always talked about a HEAVY bullet option for this round. He had settled on the 185 gr ULD RBBT design.
When he got the jackets in he quickly realized they were long enough to build a 195 gr ULD RBBT so that is what he did. I will admit I was a bit cautious about this bullet after hearing this bullet measured 1.615" in length!!! Compare that to a 130 gr Ballistic Tip at 1.220" in length and you can get an idea of the length of this bullet.
I was worried the 1-8 twist I had been using on all my 270 Allen Mag and 277 Allen Mags would not work with this bullet. We were about to find out though.
The evening we got arrived we loaded up some fireforming loads using some 150 gr bullets and made up 15 formed cases or so. The next morning we started the testing by doing a quick deelopment for velocity.
Basically consisted of loading a round and shooting it over a chronograph. Richard and I both wanted 3200 fps but would have been happy with anything over 3100 fps. We were using WC872 for powder and Fed-215 primers.
The 195 gr ULD RBBT has a pretty long baring surface and I was a bit worried that pressures would really spike as we worked up nearer to the upper end of this cartridge. We started pretty low at 88.0 gr and worked up 2 grains at a time until we reached the 98.0 gr range. Then we cut back to 1 grain increases at a time just to be a bit more conservative with the long baring surface bullet.
We stopped at 102.0 gr which was good for 3200 fps on the money. In the 80 degree temps this was what appeared to be a comfortable load. Extraction was a dream at this load and in this heat.
We then loaded up the rest of the cases with the same load and headed out to the 100 yard range to do zero the rifle 3" high at 100 yards. This was the first of the real tests to see if the 1-8 Lilja would handle this huge 270 bullet.
First shot on paper cut a perfect bullet hole, good first sign. Richard made a scope adjustment and then took another shot which showed up on paper as expected from the scope adjustments. He then fired two more shots that cut each other in half.
Now I am the first to give my rifles a plug but I will admit that this is not generally the result of 100 yard groups with a bullet of this length in a fast twist barrel but these big 195 gr ULD RBBTs seem to really hold tight even at short range which is often not really the case.
We then moved out to Richards 800 yard target and by this time the mirage was getting very bad as we were shooting over a wheat field and the humidity was really severe through out path to the target. Still we wanted to shoot at this range. We had set up the steel ram the night before and Richard took a shot at it and rolled her on the first shot.
We then shot some groups on paper at that range and got groups in the 3/4 to 1 moa range. This may not sound great but in the conditions with the mirage, I was plenty happy with this. It was about as heavy a mirage as I have seen and seeing how much that target image was floating around the crosshairs was almost hard to believe.
Interestingly enough the rifle was shooting pretty high at this range still. In fact around 12-14" or so high. We were using a BC of 0.950 in the ballistic program and still hitting much higher then expected.
Now before someone gets their shorts in a bunch, remember we were just trying to get the ballistic programs trajectory model to match that of the actual bullet flight. We are not saying this bullet has a scienticially pure BC of 0.950 but when plugged into the program, this was not enough BC to get the model to match actual bullet flight.
We did a bit more shooting but then decided to pack it in until the heat settled down.
We went back out that evening when things had cooled off nicely and the mirage was pretty much gone. Very good shooting conditions. We had tweaked the drop chart, now using a BC value of 0.975.
At this point we got a little cocky and set up the chicken steel target at 800 yards.
We took several shots at the chicken but we just did not have the rifle tuned in enough for this small target. The problem was that we were to adjustment happy when shooting in the heavy mirage and really got ourselves lost in adjustment when the mirage was gone.
We shot a three shot group on paper and was very happy to see a 2.5 to 3" triangle when we got up to the target. Being the smart fella I am I left the camera back in the car and did not even think to get it to take some pics of the groups. We were still about 8" higher then we should have been according to the ballistic program so we took an moa out of the adjustment and headed back to the take some more pot shots at the chicken. Both of us connected rather easily on the chicken although the rifle was still shooting a bit high and if we missed it was just slightly high.
THis was simply due to not having the rifle fully tuned in yet with that particular load.
Richard and I both shot the rifle to basically the same poi and both of us were very happy with the results.
We decided to replace the chicken target with the mid sized boar steel target which proved to be no problem to topple at nearly 1/2 mile. with a little more tweaking, I know for a fact in good shooting conditions that a pop can filled with water would be in serious trouble at that range with that rifle and load.
I guess you can say that the 1-8 twist barrels will handle the new 195 gr ULD RBBT accurately, at least at 3200 fps.
Again, this was out of the 277 Allen Mag which is based on the 338 Lapua parent case but I estimate that the standard 270 Allen Mag will still be able to break 3100 fps with this bullet and with the ballistic potential of this bullet, well, all you have to do is run the numbers.
Ballistically this bullet puts the 270 and 277 Allen Mag in the same class as the 7mm Allen Mag with the 200 gr ULD RBBT. In fact it is superior ballistically to the big 7mm.
Here is a pic of the 195 gr ULD RBBT compared to a 130 gr Ballistic Silvertip.
So for the first limited testing of the rifle and 195 gr ULD RBBT bullet in some very warm temps, I think it was a huge success. More to come I am sure as more 195 gr pills get out there and put in the air!!
Richard also told me there should be abough room in that jacket to get a bullet with a finish weight of 210 gr with the same bullet length. This will not improve ballistic performance as the bullet will be the same length but it will increase sectional density if someone was looking for even more penetration then what a 195 gr ULD RBBT would offer.
I would also believe that Richard could also drop bullet weight down to 185 gr with the same bullet design as long as the bullets formed well with this amount of lead in the bullet. At times the unsupported ogive will develope forming problems so that would have to be tested before saying it would work.
All in all it was a great weekend with good friends and great shooting!!!