Clean the #@$* Thing - 04/24/18
Last fall I invested in a pretty nice rig, a Cooper 300 Win Mag. 26” barrel and mounted a Vortex Scope on top. Started fireforming Nosler brass, the rifle was a tack driver with 190 grain SMKs. As soon as I had enough brass fire formed I started looking for a hunting load and started with 200G SGK. Was getting good groups. Decided to look at some other bullets but had no outstanding results so I returned to the SGKs. Wouldn’t group worth a damn. Tried the Match Kings, they sucked.
Well, throughout the winter, I wasn’t able to use the crono due to the low sun angle so I was flying wearing a blindfold. I had 350 pills down the tube and no accurate load. It would shoot 1” (sometimes) but I expected more out of this rifle. I started suspecting the rifle. I took the stock off and found the barrel making contact with stock in a 1” area at the end, under recoil. So I bought a Wheeler torque wrench so the receiver screws would be perfect as per spec. To the eye, it looks like there’s plenty of clearance, but shooting off the bipod it makes light contact. Well I’m thinking uh huh this is the problem. The receiver is spot bedded, so I installed brass shims (they’re not cheap) to give it more clearance. I had called Cooper who said to send it back and they’d fix it, but I wanted to see if it was definitely the root cause.
Went out with great anticipation and shot my Match King load. It was still lacking. By now the sun was starting to come up high enough for me to use the crono. SDs were anywhere from 7.5 to 28 with most falling around 16.
My brain cell fired and I’m thinking this bore is all carboned up. I use Wipeout to clean the barrel after every range session and followed the routine I go through with all my other rifles with one exception: the 300 has a muzzle break, and I can’t see the inside of the bore. So... I have been letting the patch tell me when the bore is clean. I always run a dry patch down the bore before I shoot, and I’d noticed a little light blue streak on the patch. No matter how much time I devoted to cleaning I’d notice that real fine streak of blue before every range session.
Ok, so I picked up some Liquid Wrench (easier and faster to get than Kroil) and some JB bore cleaner. When I started shooting semi seriously in Bradingtinton FL, the old timers there were using it to clean their barrels and swore by it, but I avoided it because I was worried about the abrasion.
So I cleaned my barrrel with it and couldn’t believe the crap that came out of that bore. I guess I did about 20 passes total before the patches looked pristine coming out.
Off to the range today. Ran the dry patch through, no blue streak.
The wind was going from 5 to howling all day but I wasn’t worried about tight groups I wanted to see the SDs. I set a target up at 250 yards and started shooting. SGK load.
My fowling shots were 2955, 2959, 2962, 2968. I then shot some 3 shot groups adjusting the charge upward. I knew they would string due to the darn wind. It blew my crono over three times grrr. My crono won’t do SD calculations with a sample size less than 5 but the velocities looked good.
Then I loaded 5 rounds with a max charge: 3063, 3078, 3070, 3068, 3065. Ave= 3068, SD 5.1. Those were shot no’s 16 - 20.
I then loaded 6 more same charge: 3071, 3060, 3057, 3066, 3052, 3050. Ave = 3059. SD = 6.9 Pretty good.
The last group I tried to bear down and shoot a good group despite the wind and was able to cover the group with my Copenhagen can. I can live with that considering the circumstances.
So what the hell. I learned something. I’ll try to avoid using the JB too much, but when I see the groups starting to open up I’ll run some JB before I change anything.
Well, throughout the winter, I wasn’t able to use the crono due to the low sun angle so I was flying wearing a blindfold. I had 350 pills down the tube and no accurate load. It would shoot 1” (sometimes) but I expected more out of this rifle. I started suspecting the rifle. I took the stock off and found the barrel making contact with stock in a 1” area at the end, under recoil. So I bought a Wheeler torque wrench so the receiver screws would be perfect as per spec. To the eye, it looks like there’s plenty of clearance, but shooting off the bipod it makes light contact. Well I’m thinking uh huh this is the problem. The receiver is spot bedded, so I installed brass shims (they’re not cheap) to give it more clearance. I had called Cooper who said to send it back and they’d fix it, but I wanted to see if it was definitely the root cause.
Went out with great anticipation and shot my Match King load. It was still lacking. By now the sun was starting to come up high enough for me to use the crono. SDs were anywhere from 7.5 to 28 with most falling around 16.
My brain cell fired and I’m thinking this bore is all carboned up. I use Wipeout to clean the barrel after every range session and followed the routine I go through with all my other rifles with one exception: the 300 has a muzzle break, and I can’t see the inside of the bore. So... I have been letting the patch tell me when the bore is clean. I always run a dry patch down the bore before I shoot, and I’d noticed a little light blue streak on the patch. No matter how much time I devoted to cleaning I’d notice that real fine streak of blue before every range session.
Ok, so I picked up some Liquid Wrench (easier and faster to get than Kroil) and some JB bore cleaner. When I started shooting semi seriously in Bradingtinton FL, the old timers there were using it to clean their barrels and swore by it, but I avoided it because I was worried about the abrasion.
So I cleaned my barrrel with it and couldn’t believe the crap that came out of that bore. I guess I did about 20 passes total before the patches looked pristine coming out.
Off to the range today. Ran the dry patch through, no blue streak.
The wind was going from 5 to howling all day but I wasn’t worried about tight groups I wanted to see the SDs. I set a target up at 250 yards and started shooting. SGK load.
My fowling shots were 2955, 2959, 2962, 2968. I then shot some 3 shot groups adjusting the charge upward. I knew they would string due to the darn wind. It blew my crono over three times grrr. My crono won’t do SD calculations with a sample size less than 5 but the velocities looked good.
Then I loaded 5 rounds with a max charge: 3063, 3078, 3070, 3068, 3065. Ave= 3068, SD 5.1. Those were shot no’s 16 - 20.
I then loaded 6 more same charge: 3071, 3060, 3057, 3066, 3052, 3050. Ave = 3059. SD = 6.9 Pretty good.
The last group I tried to bear down and shoot a good group despite the wind and was able to cover the group with my Copenhagen can. I can live with that considering the circumstances.
So what the hell. I learned something. I’ll try to avoid using the JB too much, but when I see the groups starting to open up I’ll run some JB before I change anything.