PaulS wrote:

That chart shows close matches of burn rates - not necessarily identical powders. Please always check the loads with the identical powder and bullet in the reloading manuals or from the bullet manufacturer. (I know you already know that, I'm just a worry wart!)

Paul,
Thanks for the reminder, never gets old.
I did however today during load testing go above the max load in the ADI site.
Max is listed as 19.5 grn of Ar 2207.
I tried 5 rds of 19.7 grn and 5 of 20grn.
The primers were the same shape as the minimum load, no flattening, no cratering , no stiff extraction and this is with a rear locking action.
I basically increased in .2 or .3 grain increments from 19 grns in case I would get early pressure signs.
I also have loading data from the 80s where I was running 20.5 grns of IMR 4198 with a similar projectile, that was very accurate and .1 grain below the maximum listed in the hornady manual at the time and also OVER the Sierra Manual.
Still each rifle is a law unto its self and you never know from 1 to the other, which is why we have load data from professionals to go by.
I wonder if litigation lawyers reload?
I am glad the most accurate load was .2 grn UNDER max, just so we can both sleep soundly at night

Cheers mate.

dhc4ever wrote:

Vince , Its the 55grn blitzkings that wont stabilise in my .222. You wanna buy some :)?

Sorry mate...brain fart.

I've got used to navigating Cleavers website so I know where to look for things. Biggest problem with QGE is more often than not, even though they list something they don't have it in stock.

Pete, have you try to make the OAL a bit less by seating a tiny bit deeper?
It will increase the velocity a tad so it might stabilize.

Darwin,
I was talking to a mate the other night who has the lastest Sierra reloading manual, next to the 55 grn blitzkings is a note, stating this projectile requires at least a 1 in 12 rifling twist. Should have talked to him before I bought them. Seating depth wont fix my issue, just cant spin them quick enough.
Old gun problem, fixed by using old style bullets, result, 1/2 moa group.

EDIT.
Just measured the target it was .386" for 5 shots, happy little camper here.....

Just for funI ran your 19.5 load through Quickload to get velocity and bullets length. I went to the Sierra site to get other bullet information for both the 1455 and 1350. I then used the stability calculator on the Berger site to see twist rate minimums. The 1455 is recommended for 1-10.3 and the 1350 while marginal in the 1-14 tis recommended for 1-12.5. Not perfectly inline with your experience but not far out either.

Mac,
Thanks for that.
Strangely enough the Sierra site state;
"This bullet can be an excellent choice for varmints and small game in many early 22 centrefire rifles which have a slower twist rate than commonly used today."
And the new manual recommends at least a 1 in 12 twist for the 1455's.
The 1350 are grouping well and certainly not keyholing.
What did quickload give as a velocity at 19.3 grns of AR 2207?
My estimation is something around 2950 fps ish.

Results: 222 Rem
24 inch barrel, OAL 2.130 19.5 ADI AR2207 Max Pressure 53,664 PSI

Bullet: Sierra 1350
Length: 0.690
Seating: 0.260
Pressure: 48,512 PI
FPS: 3,096

Bullet:Sierra 1455
Length: 0.790
Seating: 0.360
Pressure: 52,379
FPS: 3,141

Interesting that I get slightly different results for IMR 4198 and H 4198 with both powders being a tad slower than 2207. IMR 4198 is also compressed at 19,5 when used with the 1455. Of course Quickload is *Quick" to remind users the numbers it generates are guides, not absolutes.

The Berger Stability calculator (Miller formula) recommends twists that give a resullt at or above the calculators set "Stable" threshold. A bullet may stabilize well in a slower twist barrel but become unstable as it slows in flight. My feeling is that the calculator tends to be conservative in it's recommendations as I have a .308 with 1-12 that shoots heavier bullets accurately despite the calculators putting them in the marginally stable category.

Anytime you need some numbers run, send me a message.

Thanks Mac.
The numbers are interesting.
For the lenght of the #1455 my micometer reads .825", I wonder if your figure includes the plastic tip.
Pressures are also higher than the adi site predicts.
But like you say its an indicative program not an absolute.
Ah well if it was easy everyone would do it.
Thanks for taking the time to run those figures.

Bullet length was from the QL database. I tried to get it from the Sierra site but couldn't find it specified. I am finding that QL is pretty close in some cases but a fair bit off in others. Out of curiousity, what is your OAL with the 1455?

Edit: I checked the db www.shootforum.com/for...letdb.html and it does show the length as .79. Have you weighed them to confirm they are 55 as the first bullets in the list near that length are 65's.

2nd Edit
I was able to confirm the length of the 1455 is .825. If it was originally .790 and the same OAL used the deeper seating means higher pressures. Another reason to check everything and backing off when any component in a load changes, even a new run of bullets.