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throat.jpg
I have received my 18” Liberty barrel after having the throat scraped to safely accept factory ammunition, so it was reassembled, bedding the barrel with blue Loctite. The supplied bolt was also out of specification, so I'm due to get a replacement from Satern. In the meantime I'd ordered a second bolt from Underground Tactical. The Underground bolt is in spec. (of course) and workmanship looks great!
So I received my bolt on Saturday and quickly got my rifle and gear together to make it to the range before dark. Had to beat the winter storm due in Sunday, or it would be another week before I'd have a chance to test this build. In my haste I'd forgotten to bring my rifle rest, so I had to make due with shooting from the bench, off my range bag. Keep that in mind when looking over the accuracy results.
GrendelRifle.jpg
Function and Operation:
I ran 40 rounds of factory Hornady A-Max 123gr ammunition through the rifle. Fired brass did not exhibit any of the over pressure signs I'd seen before. No cratered or pierced primers! The primary focus of this report is on the factory A-Max ammo, but I also shot a variety of hand loads that were all loaded to published staring charge weights and C.O.L. since I want to start load development for hunting. I used the C Products Defense 25 round magazines loaded with 20 or less rounds for all strings of fire. Total round count was 70 rounds, and I'm happy to report that this rifle configuration functioned normally with no malfunctions.
A-Max Velocity:
After firing a few rounds to verify things were working right, I shot five shot strings to chronograph velocities. My chronograph is the “Shooting Chrony” model, and I set it up about 10 feet from the muzzle. Temperature was 44 deg F.
The Hornady A-Max showed: 2384, 2391, 2402, 2383, and 2401 with an average velocity of 2392 feet per second. Extreme spread is 18 fps.
100 Yard Accuracy:
I shot a couple of 5 shot groups and a 10 shot group with the Hornady A-Max . Pictures of 5 and 10 shot groups are shown here. The 5 shot group was spoiled by a flier. Overall was 2.85” and the four together measured 1.1”.
A-Max at 100 yards.jpg
The 10 shot group exhibited vertical stringing. This group was shot with two strings of 5, so that may have had something to do with it. Remember that I'm just using my range bag to rest the forearm over. All 10 shots went into 3” total and the best five were right at an inch.
A-Max 10 shots at 100.jpg
My hand loads were of the Sierra 120gr. Pro Hunter, Hornady 123gr. A-Max, and Hornady 129gr. Interlock bullets. To keep the focus on the Hornady A-Max factory ammunition, I will only say that the hand loads exhibited accuracy that was more or less similar the factory ammo. No drastic shifts were observed.
200 Yard Accuracy:
Moving to the maximum available yardage at my range, I put the factory A-Max into a couple of 5 shot groups of 2.8” and 4”. On the picture of the target, the top and bottom groups are factory ammo while the middle group is from my A-Max hand loads.
A-Max 200 group.jpg
200 yard target.jpg
My Opinion:
First, in no way am I an expert on rifle barrels or chamber specifications or reamers. I got interested in the Grendel cartridge because it works in an AR-15 and delivers enough down range performance to let me hunt deer and hogs. I like the perceived versatility of the round for all around shooting with a variety of bullet weights. I understand that part of having that versatility revolves around the chamber design with the compound throat.
I'm disappointed that my Liberty barrel, purchased from Midway under the “AR Stoner” brand, does not have the proper Grendel throat. Because of the short throat and bad bolt supplied with it, I could not safely shoot factory A-Max ammunition. While I'm glad that Satern offers to “scrape” or modify the throat to keep the bullet from contacting the lands, I would have preferred that the fix to correct the throat was such so that it produced a correct Grendel throat. I have read that Mark at PF has offered to fix these barrels so that they have a compound throat, its just that I've just decided to let Satern Machining do their work (with my shipping cost). If at the end of the day I have a barrel that will shoot the heavier pills with enough accuracy to hunt out to 300 yards or so, I'll consider this build successful. Right now it looks like that has been achieved, and I look forward to developing some accurate hunting loads for the rifle.
I have received my 18” Liberty barrel after having the throat scraped to safely accept factory ammunition, so it was reassembled, bedding the barrel with blue Loctite. The supplied bolt was also out of specification, so I'm due to get a replacement from Satern. In the meantime I'd ordered a second bolt from Underground Tactical. The Underground bolt is in spec. (of course) and workmanship looks great!
So I received my bolt on Saturday and quickly got my rifle and gear together to make it to the range before dark. Had to beat the winter storm due in Sunday, or it would be another week before I'd have a chance to test this build. In my haste I'd forgotten to bring my rifle rest, so I had to make due with shooting from the bench, off my range bag. Keep that in mind when looking over the accuracy results.
GrendelRifle.jpg
Function and Operation:
I ran 40 rounds of factory Hornady A-Max 123gr ammunition through the rifle. Fired brass did not exhibit any of the over pressure signs I'd seen before. No cratered or pierced primers! The primary focus of this report is on the factory A-Max ammo, but I also shot a variety of hand loads that were all loaded to published staring charge weights and C.O.L. since I want to start load development for hunting. I used the C Products Defense 25 round magazines loaded with 20 or less rounds for all strings of fire. Total round count was 70 rounds, and I'm happy to report that this rifle configuration functioned normally with no malfunctions.
A-Max Velocity:
After firing a few rounds to verify things were working right, I shot five shot strings to chronograph velocities. My chronograph is the “Shooting Chrony” model, and I set it up about 10 feet from the muzzle. Temperature was 44 deg F.
The Hornady A-Max showed: 2384, 2391, 2402, 2383, and 2401 with an average velocity of 2392 feet per second. Extreme spread is 18 fps.
100 Yard Accuracy:
I shot a couple of 5 shot groups and a 10 shot group with the Hornady A-Max . Pictures of 5 and 10 shot groups are shown here. The 5 shot group was spoiled by a flier. Overall was 2.85” and the four together measured 1.1”.
A-Max at 100 yards.jpg
The 10 shot group exhibited vertical stringing. This group was shot with two strings of 5, so that may have had something to do with it. Remember that I'm just using my range bag to rest the forearm over. All 10 shots went into 3” total and the best five were right at an inch.
A-Max 10 shots at 100.jpg
My hand loads were of the Sierra 120gr. Pro Hunter, Hornady 123gr. A-Max, and Hornady 129gr. Interlock bullets. To keep the focus on the Hornady A-Max factory ammunition, I will only say that the hand loads exhibited accuracy that was more or less similar the factory ammo. No drastic shifts were observed.
200 Yard Accuracy:
Moving to the maximum available yardage at my range, I put the factory A-Max into a couple of 5 shot groups of 2.8” and 4”. On the picture of the target, the top and bottom groups are factory ammo while the middle group is from my A-Max hand loads.
A-Max 200 group.jpg
200 yard target.jpg
My Opinion:
First, in no way am I an expert on rifle barrels or chamber specifications or reamers. I got interested in the Grendel cartridge because it works in an AR-15 and delivers enough down range performance to let me hunt deer and hogs. I like the perceived versatility of the round for all around shooting with a variety of bullet weights. I understand that part of having that versatility revolves around the chamber design with the compound throat.
I'm disappointed that my Liberty barrel, purchased from Midway under the “AR Stoner” brand, does not have the proper Grendel throat. Because of the short throat and bad bolt supplied with it, I could not safely shoot factory A-Max ammunition. While I'm glad that Satern offers to “scrape” or modify the throat to keep the bullet from contacting the lands, I would have preferred that the fix to correct the throat was such so that it produced a correct Grendel throat. I have read that Mark at PF has offered to fix these barrels so that they have a compound throat, its just that I've just decided to let Satern Machining do their work (with my shipping cost). If at the end of the day I have a barrel that will shoot the heavier pills with enough accuracy to hunt out to 300 yards or so, I'll consider this build successful. Right now it looks like that has been achieved, and I look forward to developing some accurate hunting loads for the rifle.
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