Post by Danny Creasy on Aug 15, 2014 19:50:14 GMT -6
I was going through shooting cabinet odds and ends last week and came across an old Eric Brooks CZ 452 Spring & Tube Kit. It was passed along in a rifle swap. The owner had installed the black tube and spring #2 in the CZ 452 American I received in the swap. It still had red, green, and blue sleeves along with the American's original factory spring (thoughtful of the seller, in case I ever sell it). Also, there were the #1, #3, and #4 replacement springs. It got me to thinking.
I got out the Lyman trigger pull gauge and checked the pull on my FS. It was 3 lbs 7 ozs. Since I don't pursue CMP Sporter that much anymore (3 lb minimum trigger required), I decided to install the #4 spring in the FS. I watched the YoDave YouTube video and then quickly had the replacement spring installed. There was no creep, so I did not need a sleeve. The weight of the new pull is 2 lbs 6 ozs. Repeated bump tests, action cycles, and safety engagements/releases yielded no issues.
I usually shoot this FS with the open sights, but I keep a big BSA Platinum 36X44 scope around in a set of Warne high tip-off rings. I often slap the scope on a hogsbacked stocked CZ for accuracy testing. I got the scope for like sixty bucks once from Midway. I know these can be junk, but this one holds a zero well (at least for rimfires) and even tracks decently. It is a bit dark, but it tends to work fine in the Alabama sunshine.
I thought a good test for the reduced trigger pull would be a run at the 25 yard USBR target in the online 25 yard game I frequent. The replacement spring makes the rifle ineligible for the RFC Box Stock Factory Sporter Class. It would have been eligible for the regular Factory Sporter Class, but that class has a 24 power scope power ceiling. So, the only option was to post a score in the Unlimited Class - that means the big guns - 40Xs, 52s, Anschutz 54 Super Match, etc.... Oh well, I've been there before and often.
This morning's conditions were nigh on perfect! Calm and 80 degrees with mixed cloud cover.
The 248-4X was my first run. One is allowed to post the best of four attempts. I never want to burn that much of my precious .22 ammo chasing my tail. So, I will seldom fire more than one target. However, I got fired up with the 248 and its two near misses (nines) and had to give a second target a try. Oh well, it was a 246-8X. If nothing else, I was tickled that the X count doubled.
Who says a full stocked rifle won't shoot?
By the way, I simply removed the scope from one of my Trainers and slid it on to the FS. This procedure works fine as long as I stick with the 11mm models. The first group is usually within a couple of inches of the POA.
The first group today was the five shot group that cut the top edge of the target. Second was the high right one. Then we got close but to the right. I kept making single clicks and shooting groups trying to not run past the little one tenth inch ten ring. Those are actually four 5 shot groups in the first two sighter bulls, and the third bull contains a group that was fired between the two in the second sighter bull. The last thing I did before starting shooting for score was to center punch the USBR shield.
I was having too much fun shooting groups. One only has 20 minutes to fire a target for score and that's including the sighters. After the USBR emblem shot, I only had 11 minutes left. Thank goodness it was so calm. I could simply single load (using the single shot adapter), aim, and squeeze without even worrying about the wind. Since I was shooting in the RFC Unlimited Class, I could use the windage and elevation tracking adjustments of my Caldwell rest for a change. Fun.
This setup might shoot a 250 with some Center-X or Tenex.
On a final note, I installed spring #1 in my CZ 452 Varmint. It too was virtually creep free but even with the tension nut bottomed out, the factory pull was 3 lbs 4 ozs. The #1 spring is supposed to yield a pull of between .75 and 1 pound. The Varmint's trigger pull weight is now 14 ozs. It tested well throughout all the safety drills, and I plan to give it a go in our regular USBR club match tomorrow. Under USBR rules, changing any factory trigger parts makes the rifle ineligible for their sporter class. So, I will shoot the Varmint in USBR Custom Class. I will use the old factory triggered American in Sporter Class tomorrow.
I got out the Lyman trigger pull gauge and checked the pull on my FS. It was 3 lbs 7 ozs. Since I don't pursue CMP Sporter that much anymore (3 lb minimum trigger required), I decided to install the #4 spring in the FS. I watched the YoDave YouTube video and then quickly had the replacement spring installed. There was no creep, so I did not need a sleeve. The weight of the new pull is 2 lbs 6 ozs. Repeated bump tests, action cycles, and safety engagements/releases yielded no issues.
I usually shoot this FS with the open sights, but I keep a big BSA Platinum 36X44 scope around in a set of Warne high tip-off rings. I often slap the scope on a hogsbacked stocked CZ for accuracy testing. I got the scope for like sixty bucks once from Midway. I know these can be junk, but this one holds a zero well (at least for rimfires) and even tracks decently. It is a bit dark, but it tends to work fine in the Alabama sunshine.
I thought a good test for the reduced trigger pull would be a run at the 25 yard USBR target in the online 25 yard game I frequent. The replacement spring makes the rifle ineligible for the RFC Box Stock Factory Sporter Class. It would have been eligible for the regular Factory Sporter Class, but that class has a 24 power scope power ceiling. So, the only option was to post a score in the Unlimited Class - that means the big guns - 40Xs, 52s, Anschutz 54 Super Match, etc.... Oh well, I've been there before and often.
This morning's conditions were nigh on perfect! Calm and 80 degrees with mixed cloud cover.
The 248-4X was my first run. One is allowed to post the best of four attempts. I never want to burn that much of my precious .22 ammo chasing my tail. So, I will seldom fire more than one target. However, I got fired up with the 248 and its two near misses (nines) and had to give a second target a try. Oh well, it was a 246-8X. If nothing else, I was tickled that the X count doubled.
Who says a full stocked rifle won't shoot?
By the way, I simply removed the scope from one of my Trainers and slid it on to the FS. This procedure works fine as long as I stick with the 11mm models. The first group is usually within a couple of inches of the POA.
The first group today was the five shot group that cut the top edge of the target. Second was the high right one. Then we got close but to the right. I kept making single clicks and shooting groups trying to not run past the little one tenth inch ten ring. Those are actually four 5 shot groups in the first two sighter bulls, and the third bull contains a group that was fired between the two in the second sighter bull. The last thing I did before starting shooting for score was to center punch the USBR shield.
I was having too much fun shooting groups. One only has 20 minutes to fire a target for score and that's including the sighters. After the USBR emblem shot, I only had 11 minutes left. Thank goodness it was so calm. I could simply single load (using the single shot adapter), aim, and squeeze without even worrying about the wind. Since I was shooting in the RFC Unlimited Class, I could use the windage and elevation tracking adjustments of my Caldwell rest for a change. Fun.
This setup might shoot a 250 with some Center-X or Tenex.
On a final note, I installed spring #1 in my CZ 452 Varmint. It too was virtually creep free but even with the tension nut bottomed out, the factory pull was 3 lbs 4 ozs. The #1 spring is supposed to yield a pull of between .75 and 1 pound. The Varmint's trigger pull weight is now 14 ozs. It tested well throughout all the safety drills, and I plan to give it a go in our regular USBR club match tomorrow. Under USBR rules, changing any factory trigger parts makes the rifle ineligible for their sporter class. So, I will shoot the Varmint in USBR Custom Class. I will use the old factory triggered American in Sporter Class tomorrow.