Cz527/.221fb

S

Stan Pollak

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Got some factory(Rem 50gr accutip-v bt) that I used to zero in with and hand some handloads(Rem brass) ranging from 15.0-16.6 gr(H4198)per the hornady manual. The factory miked out at 2.440", while my handloads were set .020" off the lands-they miked out at 2.515". Zeroing went fine with the factory. The handloads 15.0 + 15.2 also went well. When I chambered the 15.4, I blew a primer-only one of the five rounds fired. The next(15.6gr.)and first of the five rounds not only blew the primer, but locked up the bolt. It was definitely time to stop and regroup. The only other difference in my loads over the factory is the BR-4 primers vs. rem 7 1/2. Are they that much hotter than the remmys' or does my bullet seating need to get closer to the factory? I've since re-set the heads another.025"-ttl. of .045 off the lands. Stan-share your sport:)
 
primers?

In looking over my post, I realize I failed to mention that the "mike" readings were with a Stoney Point setup-the COL rdgs are-Factory 1.815",handloads 1.870(.047" off the lands). That was one of two variables I see. The other variable,and my main question , is going from a rem 7 1/2 primer to a CCI BR4 that much of a boost. I've loaded .223, .22/250, .243, and .308 with no apparent change. Input please! Stan share your sport:)
 
I've not noticed that kind of differnce using different primers in a .221 AI. I'd first check your scale. If I read your post correctly, you can pull the bullets on some of those unfired rounds and re-weigh your powder charges. Second, check the neck diameters of your loaded rounds -- if your using that junk brass Remington makes for the Fireball. One lot I bought had more "variety" than, than, well, think of something.
 
charges

I pulled several different loads and they were exactly what I'd measured out and noted. I'm in "denial" of having to go out and buy the rem 7 1/2's, but guess there is no other way. I will check those case mouths with my ball mic.-thanks for the heads up. Guess that's what assuming gets me-everytime! Stan-share your sport:)
 
In my experience the change in primers wont give the results you are getting, but reducing the jump alot will drive pressures up. 3 years ago I loaded some W748 in a .223 that was "book" safe and blew the primers flat out. I was .010 off and later found out that the load I duplicated was fired at .080 off. If the bullet shoots well from your rifle with alot of jump, just start over with the powder charges. If you really need to seat them close, then another powder like H322 or AA2015 would be good choices. Of course if the resized cases have the shoulder pushed back too far, the cases are too long, or if the firing pin hole is huge, you have a different problem. This may start some controversy, but, I have always gotten the most consistent results from seating into the lands, or .060 plus, and even up to .120 off the lands. I have gotten my best groups between .010-.030 off, but 2 days or 2 weeks later, they wouldnt shoot nearly as well. In my CZ527/.223, it likes 50gr BT at magazine length which is .120 jump, and shoots between .3 and .4 all the time.
 
sbindy

I've had such good results from every other caliber that I've reloaded close(.020"-.050")-I have an aversion to going out that much from the lands. The only other exception I've made was in the .204. I started out trying to get closer than the factory that was set back over.100", and it didn't seem to make much difference. Looks like I'll have 2 with that condition to contend with-can't argue with success!! Stan-share your sport:)
 
0n seating depth.

Have You ever wodered why seating depth affects accuracy? Some people think it is about concentricity so they seat out close to lands and sometimes they get lucky and it works,but thats all it is,just luck. What really happens is that the bullet just happens to leave the muzzle at the top or bottom of the of the accuracy window and therefore groups are good. What has to be done is :confused:to alter the moment that Your bullet leaves the muzzle so that it leaves in the accuracy window. Forget about fooling around with different powder charges to get accuracy also. Just use your cronograph to find a good strong load with small shot to shot variation then move your bullet around in big systematic seating depth increments. About three or four moves in or out will get you on to the top or bottom accuracy node. Obviously changes of seating depth will afffect pressures so always build a safety factor into your reloads. Reguards Murphy.
 
Murphy

Point well taken-will give it a try-Stan share your sport:)
 
I have a rem 700 lvsf 221 and my friend has the CZ we use reloader 7 I use 18grains with a 50 and 20 with a 40 with cci br primers, I also use lilgun 15grains with a 50 and 16 with a 40 and all bullets are seated almost touching the lands and I have no pressure problems shoots great! Maybe you should check your scale try your friends and see if it weighs the same or put a 50 grain bullet on there and see if it weighs 50.If it does I"d try a differant powder,My loads are a little hot so start a little lower.I get 3200fps with 15 grns of lilgun and the 50s and 3600 with 16 grns and the 40s. and with rel 7 I get 3150 with the 50s and 3550 40s.Maybe there is something wrong with the powder.One time a friend left some powder here and I tried some in a 22-250 load and stuck the bolt and got gas in my face on the first shot:eek:!That was the last time I tried someone elses powder!I guess he bought a keg and put the powder in smaller cans and put maskind tape on them but the one I had had no tape:mad:.
 
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