I am relatively inexperienced in the world of precision rifle shooting. Something happened this past weekend that I think I should share. I also have a number of questions at the end. I apologize for the length of this story.
For reference, I have a Tikka T3X Varmint (223 Rem) mounted in a KRG Bravo chassis.
I recently purchased five boxes of Sellier and Bellot 69g. Precision Rifle ammunition (No. 1380). Part of my preparation for shooting any ammunition is to measure four different parameters of each round in a 40-round set (2 boxes). I measure base-to-shoulder (headspace?), base-to-ogive, overall length, and bullet runout. From the first two measurements, I calculate the shoulder-to-ogive length, and sort the ammunition based on that dimension into eight groups of five for firing.
With the S&B ammo, I immediately noticed a large variation in the base-to-shoulder (B2S) measurement. Normally, I measure between .001” and .004” of variation with the factory ammo I shoot. With the B&S, I measured .013” variation in the 40 rounds measured. That’s huge! Normally, the base-to-ogive (B2O) measurement gives me a .002” to .009” spread. With the S&B, I again measured a .013” spread. More, but not so much. The OAL and runout measurements were actually pretty good, better than average. I was interested to go to the range to see how well the ammunition would shoot based on these measured variations.
The published velocity of this ammunition is 3018 fps. I take the manufacturer claims of velocity with a grain of salt – sometimes a large grain. Federal Gold Medal 69g. (GM223M) claims a muzzle velocity of 2950 fps, but in my rifle, I get an average of 2831 fps. Fiocchi Exacta 69g. (223MKC) claims 2850 fps, but in my rifle, I get an average of 2741 fps. Winchester Match 69g. claims 3060 fps, but I get an average of 2693 fps. This Sellier and Bellot claimed 3018 fps, but at the range I was measuring velocities of between 3017 and 3072 fps. When I saw these values on my chronograph, my eyebrows went up, but that was all. Here is where more precision rifle shooting knowledge and experience probably would have paid off, but I didn’t have it.
After 25 rounds, 5 groups of 5 shots without incident, I started on the 6th group. When I pulled the trigger on round #26, I felt a blast of air/gas/something hit my face. It startled me. I could see that the round hit the target in the expected location. I thought I noticed a different smell from the shot. When I tried to eject the round, the bolt was very difficult to lift. With some effort, I was finally able to eject the casing, which I examined. To my untrained eye, there didn’t appear to be anything wrong with the casing, but I saved it anyways. I reinserted the magazine and fired round #27. The same thing happened, but maybe with less severity. Not as much “blowback”, and not as difficult to lift the bolt. More difficult than normal, but not as bad as round #26. I again examined the casing and also removed the bolt from the rifle to examine that. To my eye, everything looked fine. I was able to run the bolt normally without a magazine inserted into the rifle. So, I reloaded and fired round #28. This round went off much the same as #26 with a noticeable slap in the face from some sort of high-speed pressure wave. At that point, I discontinued shooting and packed up. I saved casings from rounds #26, #27 and #28, and also grabbed 5 more casings from earlier rounds that I didn’t have a problem with.
At this point, on the drive home, I suspected there might have been an overpressure issue, but I hadn’t expected this from factory-produced ammo. Once home, I did some research on the signs of overpressure and that is exactly what I think happened. The five casings I collected and #27 had cratered primers with raised edges around the firing pin dent. Rounds #26 and #28 had very deep pockets in the primers from the firing pin; almost like caves. The faces of all primers seem very flat to the edge. Also, upon inspecting the bolt face of my rifle, I can see a primer-sized ring around the firing pin hole. In my opinion, this ammo is not safe to use.
I am surprised that factory-produced ammo is loaded this hot. Knowing what I know now, I should have inspected the primers after I first saw such high velocities. They were 200 to 350 fps faster than other 69g. ammo in my rifle. At the range, I didn’t know how much faster these rounds were, but I knew they were pretty fast.
So, for those who have stuck with my story to this point, a few questions:
1. Do I need to have my rifle inspected by a gunsmith?
2. What components of the rifle could have been damaged by these high-pressure rounds? I looked at the barrel with my borescope, but don't see anything abnormal there. Could something within the bolt assembly be damaged?
3. Should I contact the company where I bought the ammo to advise them of what happened?
4. What should I do with the remaining 3 boxes of ammo? I don’t think they would be safe for anyone to fire. Correct?
I learned a valuable lesson here and I hope others can find some value in my experience. I’m happy that I wasn’t hurt. I hope my rifle escaped unscathed.
Cheers.
Steven
Photos: Boltface1 and Boltface2 - not cleaned after the range to preserve coloration.
Photos: Normal1 and Normal2 - a casing I have fired in the past. Just for reference.
Photos: SandB01 and SandB02 - a casing from shots 1 thru 25. Note cratering on the primer.
Photos: SandB26a and SandB26b - casing from shot #26. Deep hole in primer. #28 looks very similar.
For reference, I have a Tikka T3X Varmint (223 Rem) mounted in a KRG Bravo chassis.
I recently purchased five boxes of Sellier and Bellot 69g. Precision Rifle ammunition (No. 1380). Part of my preparation for shooting any ammunition is to measure four different parameters of each round in a 40-round set (2 boxes). I measure base-to-shoulder (headspace?), base-to-ogive, overall length, and bullet runout. From the first two measurements, I calculate the shoulder-to-ogive length, and sort the ammunition based on that dimension into eight groups of five for firing.
With the S&B ammo, I immediately noticed a large variation in the base-to-shoulder (B2S) measurement. Normally, I measure between .001” and .004” of variation with the factory ammo I shoot. With the B&S, I measured .013” variation in the 40 rounds measured. That’s huge! Normally, the base-to-ogive (B2O) measurement gives me a .002” to .009” spread. With the S&B, I again measured a .013” spread. More, but not so much. The OAL and runout measurements were actually pretty good, better than average. I was interested to go to the range to see how well the ammunition would shoot based on these measured variations.
The published velocity of this ammunition is 3018 fps. I take the manufacturer claims of velocity with a grain of salt – sometimes a large grain. Federal Gold Medal 69g. (GM223M) claims a muzzle velocity of 2950 fps, but in my rifle, I get an average of 2831 fps. Fiocchi Exacta 69g. (223MKC) claims 2850 fps, but in my rifle, I get an average of 2741 fps. Winchester Match 69g. claims 3060 fps, but I get an average of 2693 fps. This Sellier and Bellot claimed 3018 fps, but at the range I was measuring velocities of between 3017 and 3072 fps. When I saw these values on my chronograph, my eyebrows went up, but that was all. Here is where more precision rifle shooting knowledge and experience probably would have paid off, but I didn’t have it.
After 25 rounds, 5 groups of 5 shots without incident, I started on the 6th group. When I pulled the trigger on round #26, I felt a blast of air/gas/something hit my face. It startled me. I could see that the round hit the target in the expected location. I thought I noticed a different smell from the shot. When I tried to eject the round, the bolt was very difficult to lift. With some effort, I was finally able to eject the casing, which I examined. To my untrained eye, there didn’t appear to be anything wrong with the casing, but I saved it anyways. I reinserted the magazine and fired round #27. The same thing happened, but maybe with less severity. Not as much “blowback”, and not as difficult to lift the bolt. More difficult than normal, but not as bad as round #26. I again examined the casing and also removed the bolt from the rifle to examine that. To my eye, everything looked fine. I was able to run the bolt normally without a magazine inserted into the rifle. So, I reloaded and fired round #28. This round went off much the same as #26 with a noticeable slap in the face from some sort of high-speed pressure wave. At that point, I discontinued shooting and packed up. I saved casings from rounds #26, #27 and #28, and also grabbed 5 more casings from earlier rounds that I didn’t have a problem with.
At this point, on the drive home, I suspected there might have been an overpressure issue, but I hadn’t expected this from factory-produced ammo. Once home, I did some research on the signs of overpressure and that is exactly what I think happened. The five casings I collected and #27 had cratered primers with raised edges around the firing pin dent. Rounds #26 and #28 had very deep pockets in the primers from the firing pin; almost like caves. The faces of all primers seem very flat to the edge. Also, upon inspecting the bolt face of my rifle, I can see a primer-sized ring around the firing pin hole. In my opinion, this ammo is not safe to use.
I am surprised that factory-produced ammo is loaded this hot. Knowing what I know now, I should have inspected the primers after I first saw such high velocities. They were 200 to 350 fps faster than other 69g. ammo in my rifle. At the range, I didn’t know how much faster these rounds were, but I knew they were pretty fast.
So, for those who have stuck with my story to this point, a few questions:
1. Do I need to have my rifle inspected by a gunsmith?
2. What components of the rifle could have been damaged by these high-pressure rounds? I looked at the barrel with my borescope, but don't see anything abnormal there. Could something within the bolt assembly be damaged?
3. Should I contact the company where I bought the ammo to advise them of what happened?
4. What should I do with the remaining 3 boxes of ammo? I don’t think they would be safe for anyone to fire. Correct?
I learned a valuable lesson here and I hope others can find some value in my experience. I’m happy that I wasn’t hurt. I hope my rifle escaped unscathed.
Cheers.
Steven
Photos: Boltface1 and Boltface2 - not cleaned after the range to preserve coloration.
Photos: Normal1 and Normal2 - a casing I have fired in the past. Just for reference.
Photos: SandB01 and SandB02 - a casing from shots 1 thru 25. Note cratering on the primer.
Photos: SandB26a and SandB26b - casing from shot #26. Deep hole in primer. #28 looks very similar.
