22 Whisper... er X 28 ????

Magnum Wheel Man · June 6, 2009, 02:51 PM

most know by now that I'm playing with the 5.7 X 28 with my Contender barrel used for the tests, & later... maybe... "safe" loads to run through my FN later...

with the twist rate of the 5.7 X 28, I thought I could run up to & possibly heavier than some 68 grain Hornady HPBT match bullets I have... I started out with some 40 grain V Max bullets & several powders, this week I got some 33 Grain Speer TNT's to try as well... but today I loaded the test loads of the 68 grain bullets... I was suprised that the bullets were almost as long as the case...

later this summer I'll break out the chrony, & shoot the groups of 10 of each load & see where I'm at...

I wonder if the "heavy's" will stabilize well & where we'll be in velocity... maybe even subsonic with some loads... hopefully some tight groups in the bunch...

anyone else play with heavy 22 bullets in tight twist barrels ???

what powders have you found to work well ???

**Unclenick** · June 6, 2009, 03:02 PM

Go to my shooting file repository and download the bullet_stability_and_twist_estimator file. It is an Excel file and you have to have either Excel or Calc on your machine to run it. (Calc is an Excel compatible spreadsheet program that comes as part of the free Open Office Suite, so you don't have to buy anything to use the file.) Fill in the blanks. It will calculate a stability factor, s, for your bullet and its velocity, weight, and weather conditions. As long as that number is bigger than 1, the bullet should be stable, but having it about 1.4-1.5 is usually best. Numbers higher than that will also work, though the accuracy might not be quite up to the potential for an ideal twist. It depends how well the bullets are made.

June 6, 2009, 02:51 PM	#1
Magnum Wheel Man Senior Member Join Date: July 26, 2006 Location: Southern Minnesota Posts: 9,333	22 Whisper... er X 28 ???? most know by now that I'm playing with the 5.7 X 28 with my Contender barrel used for the tests, & later... maybe... "safe" loads to run through my FN later... with the twist rate of the 5.7 X 28, I thought I could run up to & possibly heavier than some 68 grain Hornady HPBT match bullets I have... I started out with some 40 grain V Max bullets & several powders, this week I got some 33 Grain Speer TNT's to try as well... but today I loaded the test loads of the 68 grain bullets... I was suprised that the bullets were almost as long as the case... later this summer I'll break out the chrony, & shoot the groups of 10 of each load & see where I'm at... I wonder if the "heavy's" will stabilize well & where we'll be in velocity... maybe even subsonic with some loads... hopefully some tight groups in the bunch... anyone else play with heavy 22 bullets in tight twist barrels ??? what powders have you found to work well ??? __________________ In life you either make dust or eat dust...

June 6, 2009, 03:02 PM	#2
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,060	Go to my shooting file repository and download the bullet_stability_and_twist_estimator file. It is an Excel file and you have to have either Excel or Calc on your machine to run it. (Calc is an Excel compatible spreadsheet program that comes as part of the free Open Office Suite, so you don't have to buy anything to use the file.) Fill in the blanks. It will calculate a stability factor, s, for your bullet and its velocity, weight, and weather conditions. As long as that number is bigger than 1, the bullet should be stable, but having it about 1.4-1.5 is usually best. Numbers higher than that will also work, though the accuracy might not be quite up to the potential for an ideal twist. It depends how well the bullets are made. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

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