Molon
02-20-23, 16:52
Safety Warning for Berger 77 grain OTM Tactical Ammunition: Pressure Testing Update
This is a safety warning pertaining to Berger’s factory loaded ammunition.
Berger 223 Remington
77 grain OTM Tactical
Part # 65-23030
Lot # P002745-1
https://www.ar15.com/media/mediaFiles/28568/beger_kaboom_box-2018309.jpg
https://www.ar15.com/media/mediaFiles/28568/berger_kaboom_lot_number-2018317.jpg
While firing this ammunition from one of my Krieger barreled, semi-automatic, precision AR-15s, I experienced an uncharacteristic amount of recoil and muzzle blast. This occurred with the second round fired from the magazine and there were two bullet holes in the target, so there was no type of bore obstruction involved. (This AR-15 has functioned flawlessly for over one thousand rounds and has produced ˝ MOA 10-shot groups at 100 yards.)
The action failed to cycle after firing this second round from the magazine and the trigger was dead. No amount pulling/pounding on the charging handle was able to free-up the bolt carrier group. As stated above, there were two bullet holes in the target so there was no type of bore instruction involved.
At home, I had to use a mallet and a Delrin rod to pound the bolt, carrier and case out of the barrel extension/upper receiver. Prior to pounding out the bolt carrier group, I took a quick look in the bore with a cheap borescope. It was clearly visible that the brass case (Lapua) was still tightly sealed to the walls of the chamber.
https://www.ar15.com/media/mediaFiles/28568/berger_kaboom_borescope-2018316.jpg
Upon examining the spent case, it was clearly visible that the primer pocket was greatly expanded and there was a large amount of ejector and extractor brass-flow. The primer fell out of the bolt face when the case was removed with the pounding-out of the bolt carrier group.
https://www.ar15.com/media/mediaFiles/28568/berger_kaboom_03-2018310.jpg
https://www.ar15.com/media/mediaFiles/28568/berger_kaboom_04-2018311.jpg
https://www.ar15.com/media/mediaFiles/28568/berger_kaboom_03-2018310.jpg
There was a large “belt” of expanded brass just above the extractor groove. This belt had a diameter of 0.414” at the at the broadest section. The case was split on either side of the extractor brass flow. The case rim was split at the ejector brass flow.
https://www.ar15.com/media/mediaFiles/28568/berger_kaboom_05-2018312.jpg
https://www.ar15.com/media/mediaFiles/28568/berger_kaboom_07-2018314.jpg
This Krieger barrel has a 223 Remington chamber with a 1:9" twist. This barrel was purchased directly from Krieger Barrels, Inc. and was chambered by them. I've fired over a thousand trouble-free rounds through this barrel. The box label for this Berger ammunition clearly states that this is 223 Remington ammunition.
Using a bullet pulled from this lot of ammunition, I determined the cartridge overall length that would be necessary for the bullet to be seated to the lands of this barrel. That distance was 2.322" and since the factory loaded ammunition was loaded to magazine length, the bullet was nowhere near the lands of my barrel.
https://www.ar15.com/media/mediaFiles/28568/sinclair_seating_dpeth_gauge_02_resized-1378837.jpg
Shortly before shooting this Berger factory loaded ammunition, I fired a 10-shot group of factory loaded Sierra Prairie Enemy 55 grain BlitzKings. That group had an extreme spread of 0.72 MOA.
https://www.ar15.com/media/mediaFiles/28568/sierra_prairie_enemy_10_shot_group_at_10-2020487.jpg
https://www.ar15.com/media/mediaFiles/28568/berger_kaboom_casehead_letters_01-2021963.jpg
The bolt (the image is flipped)
https://www.ar15.com/media/mediaFiles/28568/berger_engraved_bolt_face_02-2021962.jpg
The blown case has a weight of 99.0 grains. The neck diameter of this case is 0.254”. The diameter of the “belt” above the extractor groove is 0.414” at the broadest section.
The diameter of the case rim across the extractor and ejector brass flow is 0.423” and the diameter of the case rim rotated to 90 degrees of that position is 0.382”. The primer pocket has a diameter of approximately 0.222” at the broadest section.
I pulled-down 20 of the unfired cartridges from this lot of ammunition. Here’s the compiled data.
https://www.ar15.com/media/mediaFiles/28568/berger_factory_ammunition_data_sheet_02_-2025493.jpg
Pulled-down powder charge weights . . .
https://www.ar15.com/media/mediaFiles/28568/sample_standard_deviaiton_of_powder_char-2026901.jpg
I pulled-down a couple more rounds after compiling the above data and found a round with a charge of 23.6 grains. The puts the powder charge variation at 1.8 grains.
https://www.ar15.com/media/mediaFiles/28568/powder_charge_graph_003-2062310.jpg
This ammunition is a heavily compressed load, so bullet set-back is highly improbable. Since it was a compressed load, I was unable to use my custom K&M compression gauge to obtain an accurate measure of neck tension, however, it required quite a bit of force to pull the bullets from the cases using a press-mounted, collet bullet-puller. Also, using the custom K&M compression gauge, I applied 90 pounds of force to one of the factory-loaded cartridges that had a cartridge overall length of 2.253". After applying the 90 pounds of force, I again measured the COAL. It was still 2.253".
https://www.ar15.com/media/mediaFiles/28568/compression_gauge_03-2021600.jpg
Pulled-down powder . . .
28.6 grains of this pulled-down powder filled a randomly selected pulled-down case to the case mouth. The longest cartridge overall length that I measured from this lot of factory loaded ammunition was 2.262". I was able to load 26.0 grains of the pulled-down powder into a pulled-down case and seat a pulled-down bullet to a cartridge overall length of 2.262".
Pulled-down case weights . . .
https://www.ar15.com/media/mediaFiles/28568/sample_standard_deviaiton_of_case_weight-2026909.jpg
The case weights past the plus one standard deviation are the heaviest Lapua Match cases that I've ever seen. (Legacy"standard" Lapua cases did weigh more.)
From Berger . . .
----
Berger has reached out to me and offered to replace this ammunition. They also said ".We have had a couple of these reports. But it dosent seem an issue with all of this ammunition."
-----
Berger is sending me a call-tag for the unfired rounds. Berger also stated, "there has been a change in this load between the lot that you have and the lot that we are sending you. The new load was developed in a standard SAAMI 223 Remington chamber."
(I decided to keep this lot of ammunition and considered having it pressure tested.)
-----
continued in next post . . .
This is a safety warning pertaining to Berger’s factory loaded ammunition.
Berger 223 Remington
77 grain OTM Tactical
Part # 65-23030
Lot # P002745-1
https://www.ar15.com/media/mediaFiles/28568/beger_kaboom_box-2018309.jpg
https://www.ar15.com/media/mediaFiles/28568/berger_kaboom_lot_number-2018317.jpg
While firing this ammunition from one of my Krieger barreled, semi-automatic, precision AR-15s, I experienced an uncharacteristic amount of recoil and muzzle blast. This occurred with the second round fired from the magazine and there were two bullet holes in the target, so there was no type of bore obstruction involved. (This AR-15 has functioned flawlessly for over one thousand rounds and has produced ˝ MOA 10-shot groups at 100 yards.)
The action failed to cycle after firing this second round from the magazine and the trigger was dead. No amount pulling/pounding on the charging handle was able to free-up the bolt carrier group. As stated above, there were two bullet holes in the target so there was no type of bore instruction involved.
At home, I had to use a mallet and a Delrin rod to pound the bolt, carrier and case out of the barrel extension/upper receiver. Prior to pounding out the bolt carrier group, I took a quick look in the bore with a cheap borescope. It was clearly visible that the brass case (Lapua) was still tightly sealed to the walls of the chamber.
https://www.ar15.com/media/mediaFiles/28568/berger_kaboom_borescope-2018316.jpg
Upon examining the spent case, it was clearly visible that the primer pocket was greatly expanded and there was a large amount of ejector and extractor brass-flow. The primer fell out of the bolt face when the case was removed with the pounding-out of the bolt carrier group.
https://www.ar15.com/media/mediaFiles/28568/berger_kaboom_03-2018310.jpg
https://www.ar15.com/media/mediaFiles/28568/berger_kaboom_04-2018311.jpg
https://www.ar15.com/media/mediaFiles/28568/berger_kaboom_03-2018310.jpg
There was a large “belt” of expanded brass just above the extractor groove. This belt had a diameter of 0.414” at the at the broadest section. The case was split on either side of the extractor brass flow. The case rim was split at the ejector brass flow.
https://www.ar15.com/media/mediaFiles/28568/berger_kaboom_05-2018312.jpg
https://www.ar15.com/media/mediaFiles/28568/berger_kaboom_07-2018314.jpg
This Krieger barrel has a 223 Remington chamber with a 1:9" twist. This barrel was purchased directly from Krieger Barrels, Inc. and was chambered by them. I've fired over a thousand trouble-free rounds through this barrel. The box label for this Berger ammunition clearly states that this is 223 Remington ammunition.
Using a bullet pulled from this lot of ammunition, I determined the cartridge overall length that would be necessary for the bullet to be seated to the lands of this barrel. That distance was 2.322" and since the factory loaded ammunition was loaded to magazine length, the bullet was nowhere near the lands of my barrel.
https://www.ar15.com/media/mediaFiles/28568/sinclair_seating_dpeth_gauge_02_resized-1378837.jpg
Shortly before shooting this Berger factory loaded ammunition, I fired a 10-shot group of factory loaded Sierra Prairie Enemy 55 grain BlitzKings. That group had an extreme spread of 0.72 MOA.
https://www.ar15.com/media/mediaFiles/28568/sierra_prairie_enemy_10_shot_group_at_10-2020487.jpg
https://www.ar15.com/media/mediaFiles/28568/berger_kaboom_casehead_letters_01-2021963.jpg
The bolt (the image is flipped)
https://www.ar15.com/media/mediaFiles/28568/berger_engraved_bolt_face_02-2021962.jpg
The blown case has a weight of 99.0 grains. The neck diameter of this case is 0.254”. The diameter of the “belt” above the extractor groove is 0.414” at the broadest section.
The diameter of the case rim across the extractor and ejector brass flow is 0.423” and the diameter of the case rim rotated to 90 degrees of that position is 0.382”. The primer pocket has a diameter of approximately 0.222” at the broadest section.
I pulled-down 20 of the unfired cartridges from this lot of ammunition. Here’s the compiled data.
https://www.ar15.com/media/mediaFiles/28568/berger_factory_ammunition_data_sheet_02_-2025493.jpg
Pulled-down powder charge weights . . .
https://www.ar15.com/media/mediaFiles/28568/sample_standard_deviaiton_of_powder_char-2026901.jpg
I pulled-down a couple more rounds after compiling the above data and found a round with a charge of 23.6 grains. The puts the powder charge variation at 1.8 grains.
https://www.ar15.com/media/mediaFiles/28568/powder_charge_graph_003-2062310.jpg
This ammunition is a heavily compressed load, so bullet set-back is highly improbable. Since it was a compressed load, I was unable to use my custom K&M compression gauge to obtain an accurate measure of neck tension, however, it required quite a bit of force to pull the bullets from the cases using a press-mounted, collet bullet-puller. Also, using the custom K&M compression gauge, I applied 90 pounds of force to one of the factory-loaded cartridges that had a cartridge overall length of 2.253". After applying the 90 pounds of force, I again measured the COAL. It was still 2.253".
https://www.ar15.com/media/mediaFiles/28568/compression_gauge_03-2021600.jpg
Pulled-down powder . . .
28.6 grains of this pulled-down powder filled a randomly selected pulled-down case to the case mouth. The longest cartridge overall length that I measured from this lot of factory loaded ammunition was 2.262". I was able to load 26.0 grains of the pulled-down powder into a pulled-down case and seat a pulled-down bullet to a cartridge overall length of 2.262".
Pulled-down case weights . . .
https://www.ar15.com/media/mediaFiles/28568/sample_standard_deviaiton_of_case_weight-2026909.jpg
The case weights past the plus one standard deviation are the heaviest Lapua Match cases that I've ever seen. (Legacy"standard" Lapua cases did weigh more.)
From Berger . . .
----
Berger has reached out to me and offered to replace this ammunition. They also said ".We have had a couple of these reports. But it dosent seem an issue with all of this ammunition."
-----
Berger is sending me a call-tag for the unfired rounds. Berger also stated, "there has been a change in this load between the lot that you have and the lot that we are sending you. The new load was developed in a standard SAAMI 223 Remington chamber."
(I decided to keep this lot of ammunition and considered having it pressure tested.)
-----
continued in next post . . .