Buffalobob
Well-Known Member
In 2005, Kirby built me a 7AM on a Nesika action and 34 inch Lilja 9 twist barrel. I ordered 500 of the 200 gr ULD RBBT Wildcat bullets. Kirby estimated that the rifle would last 20 years if used as a hunting rifle. I have had it 12 years and fired maybe 350 rounds through it for about 30 rounds per year. It has killed about 8-10 animals at 800 to 1100 yard range. I have always used the original load that Kirby gave me of 102 (or 103) grains of US869 and Fed 215 M primers being as it has always been 0.5 MOA. At 103 grains of powder the muzzle velocity is about 3330 fps measured by Magnetospeed.
So being a little bored, I decided to order some of the new Berger 195s and the Sierra 197s and see what kind of results I could get from them. First thing I did was to measure the bearing surface of each to see how they compared to the Wildcats. The Wildcats with the RBBT had a significantly longer bearing surface than the other two. I was a little concerned that the Sierra jacket might be tougher than the others so I started it with a little lower powder charge. I fired two rounds for each half grain increment waiting about 8-10 minutes between shots being as the ambient temperature was around 85- 90 degrees. The bullets had been kept in a cooler and were about 50-60 degrees when fired. I did not let them sit in the chamber and get hot before firing.
WARNING – THIS IS MY CHAMBER CUT IN 2005 BY THE REAMER KIRBY WAS USING THEN. I DO NOT KNOW WHAT REAMER HE IS USING NOW!!!!!!!!!!!!!!!!
Sierra 197 grain HPBT
Powder US 869, Primer Federal 215GM, Case 338 Lapua, Bullets seated to touch but not jammed.
COL = 3.750
Charge -- Velocity
101.0 -- 3282
101.0 -- 3287
101.5 -- 3290
101.5 -- 3288
102.0 -- 3288
102.0 -- 3300
102.5 -- 3322
102.5 -- 3338
103.0 -- 3339
103.0 -- 3337
Interestingly, the Sierra 197grain HPBT at 103 grains of powder gives the same velocity as the Wildcat 200 grain RBBT. Bolt lift was fine and there were only light extractor marks.
Berger 195 grain HPBT
Powder US 869, Primer Federal 215GM, Case 338 Lapua, Bullets seated to touch but not jammed.
COL = 3.705
Charge Velocity
101.5 -- 3284
101.5 -- No Reading
102.0 -- 3331
102.0 -- No reading – strap on Magneto Speed had worked loose
102.5 -- 3329
102.5 -- 3343
103.0 -- 3374
103.0 -- 3357
103.5 -- 3369
103.5 -- 3378
It might be that the charge could be increased to 104 grains being as bolt lift was still OK and there was not really a lot of extractor marks on the case. At a top velocity of about 3375 fps there is more than enough speed and the two bullets on the target are center to center about 0.4 which is acceptable accuracy for hunting at 1000 yards.
On the target the upper two groups on the left side are five shot groups of the Wildcat 200. I am checking accuracy and muzzle velocity of bullets that were loaded three years ago against bullets that I have just loosened up in the case.
On the left row on the target, the third, fourth and fifth down groups are Bergers as well as all of the center row groups. While waiting for the barrel to cool between shots, I forgot which piece of tape I was supposed to shoot at and there are two one shot groups in the middle of the center row (just a little mental error on my part). Accuracy is not quite 0.5 MOA for all of the groups but probably can be improved by playing around with seating depth.
The right hand side row are all Sierra two shot groups with lowest charge at the top and maximum at the bottom. The center to center spacing is less than 0.5 MOA on four of them, so accuracy is very promising.
Just to say it one more time ---
WARNING – THIS IS MY CHAMBER CUT IN 2005 BY THE REAMER KIRBY WAS USING THEN. I DO NOT KNOW WHAT REAMER HE IS USING NOW!!!!!!!!!!!!!!!!
AS a footnote – I once tested Cauterico 189 grain HPBTs with both WC872 and US869 and could not get them to group under one MOA. So the rifle does not shoot just any bullet I try.
And lastly, I have no plans to hunt with either the Sierra or the Berger. The Wildcats work fine on everything from antelope to deer to elk and I have plenty left.
So being a little bored, I decided to order some of the new Berger 195s and the Sierra 197s and see what kind of results I could get from them. First thing I did was to measure the bearing surface of each to see how they compared to the Wildcats. The Wildcats with the RBBT had a significantly longer bearing surface than the other two. I was a little concerned that the Sierra jacket might be tougher than the others so I started it with a little lower powder charge. I fired two rounds for each half grain increment waiting about 8-10 minutes between shots being as the ambient temperature was around 85- 90 degrees. The bullets had been kept in a cooler and were about 50-60 degrees when fired. I did not let them sit in the chamber and get hot before firing.
WARNING – THIS IS MY CHAMBER CUT IN 2005 BY THE REAMER KIRBY WAS USING THEN. I DO NOT KNOW WHAT REAMER HE IS USING NOW!!!!!!!!!!!!!!!!
Sierra 197 grain HPBT
Powder US 869, Primer Federal 215GM, Case 338 Lapua, Bullets seated to touch but not jammed.
COL = 3.750
Charge -- Velocity
101.0 -- 3282
101.0 -- 3287
101.5 -- 3290
101.5 -- 3288
102.0 -- 3288
102.0 -- 3300
102.5 -- 3322
102.5 -- 3338
103.0 -- 3339
103.0 -- 3337
Interestingly, the Sierra 197grain HPBT at 103 grains of powder gives the same velocity as the Wildcat 200 grain RBBT. Bolt lift was fine and there were only light extractor marks.
Berger 195 grain HPBT
Powder US 869, Primer Federal 215GM, Case 338 Lapua, Bullets seated to touch but not jammed.
COL = 3.705
Charge Velocity
101.5 -- 3284
101.5 -- No Reading
102.0 -- 3331
102.0 -- No reading – strap on Magneto Speed had worked loose
102.5 -- 3329
102.5 -- 3343
103.0 -- 3374
103.0 -- 3357
103.5 -- 3369
103.5 -- 3378
It might be that the charge could be increased to 104 grains being as bolt lift was still OK and there was not really a lot of extractor marks on the case. At a top velocity of about 3375 fps there is more than enough speed and the two bullets on the target are center to center about 0.4 which is acceptable accuracy for hunting at 1000 yards.
On the target the upper two groups on the left side are five shot groups of the Wildcat 200. I am checking accuracy and muzzle velocity of bullets that were loaded three years ago against bullets that I have just loosened up in the case.
On the left row on the target, the third, fourth and fifth down groups are Bergers as well as all of the center row groups. While waiting for the barrel to cool between shots, I forgot which piece of tape I was supposed to shoot at and there are two one shot groups in the middle of the center row (just a little mental error on my part). Accuracy is not quite 0.5 MOA for all of the groups but probably can be improved by playing around with seating depth.
The right hand side row are all Sierra two shot groups with lowest charge at the top and maximum at the bottom. The center to center spacing is less than 0.5 MOA on four of them, so accuracy is very promising.
Just to say it one more time ---
WARNING – THIS IS MY CHAMBER CUT IN 2005 BY THE REAMER KIRBY WAS USING THEN. I DO NOT KNOW WHAT REAMER HE IS USING NOW!!!!!!!!!!!!!!!!
AS a footnote – I once tested Cauterico 189 grain HPBTs with both WC872 and US869 and could not get them to group under one MOA. So the rifle does not shoot just any bullet I try.
And lastly, I have no plans to hunt with either the Sierra or the Berger. The Wildcats work fine on everything from antelope to deer to elk and I have plenty left.
