221 fb

[varmintshooter]

Went to the range yesterday with new CZ527 in 221 fb. shooting 50 gr vmax and RL7, rem 7.5 primers, and PMC brass (formed from 223). I started @ 17.7 gr and worked up to 18.6 gr in .3 gr increments. Groups were @ 1" or just under @ 100 yds.

17.7 gr 3 shot avg 3144
18 gr 5 shot avg 3202
18.3 gr 5 shot avg 3250
18.6 gr 3 shot avg 3304

None of the loads showed any sign of high pressure, but they are all about 200 fps above book #'s. This is my first exp. with RL7 and it seems to good to be true.
All shooting @ sea level 90* f with 10-15 mph wind and 22" 12 twist barrel. Is this normal?

 

[bheadboy]

your velocities are significantly higher than normal for 50gr

the groups are telling you this is not a good node, 221's will normally go into the .500 at 100 with first workups,

I would back off, look for 221 brass, as 223 is heavier thus maybe part of your problem

if you need to use 222 to down size,

Bob

 

[Ackman]

Keep working at it. Barrels can like one bullet and not another.....try different things. And 10-15mph wind isn't helping, your groups will be tighter in less wind. I've always had great luck with RL7 and 40gr bullets in the Fireball. Your brass is stronger and better than Rem. 221 and will handle higher pressures....don't worry about the velocity, just find best accuracy and the speed will be whatever it is.

 

[varmintshooter]

Thanks guys.
I was surprised by these velocities but there were no pressure issues. The 223 brass is rated for higher pressure than 221 and 221 brass is rated for higher pressure than 222 brass. Being as the brass is the weak point in a load and if there is no sign of high pressure, what gives?
Adam B had similar results with a 20 vt and LC brass. Don't get me wrong I don't claim to be an expert, I'm just trying to figure things out.
Originally I planned to shoot 40 gr vmax but RL7 was not a recommended powder with 40 gr bullets.

 

[LitLBoy]

Try little gun powder with the 40 grain bullets, you should be able to work up to 16.2 gr.
LitLBoy

 

[Geronimo Jim]

15 grains of Lil'Gun and 40 gr V Max gives me 1430 fps and no pressure AND
big holes.

 

[varmintshooter]

I have ruled out LILGUN as it would give unexplained flyers ( 6" or more ) and was to inconsistent.
Velocity was right at 3600 with the 40 gr vmax. this was in a cooper model 38.

 

[Ackman]

1) Being as the brass is the weak point in a load and if there is no sign of high pressure, what gives?
Adam B had similar results with a 20 vt and LC brass. Don't get me wrong I don't claim to be an expert, I'm just trying to figure things out.

2) Originally I planned to shoot 40 gr vmax but RL7 was not a recommended powder with 40 gr bullets.

1) Brass can make a big difference. A friend once told me his .223 brass - it was either Win. or Rem. - would blow primer pockets with the load I shoot using IMI brass. Now Remington Fireball brass isn't real hard compared to others, and is very much tested when necked to .17. This same friend got tired of loose primer pockets in his 17MIV and started making brass from .223, I believe it was IMI.......he stopped losing primer pockets and shoots loads another 150fps or so faster.

2) Whoever said RL7 was not recommended with 40's is dead wrong, has no clue. Don't ever listen to them again. I'd guess the majority of people shooting a .221 are doing it with 40's, and RL7 is known to be one of the really good powders. My load is 19.8gr with a 40gr bullet @ 3450. And yes that's more/faster than the Sierra manual says.

 

[Charles]

I shoot N-120, 1/4 at 100 3/4 at 200 yds. made some PD shot a little over 300. Remington Brass on the third loading primer pockets starting to get loose. Shooting 40 gr. v-max

 

[Witchhunter]

I use 14.8 grains of 2400 in mine behind a 40 grain Sierra HP. This shoots well in my contender.

 

[stacy]

H-4227 IN MY FIREBALL WITH 40GR HP BERGERS 205 FED =BUGHOLES