[howdahpistol]

2.9 grains of True Blue behind a Sierra #1355 55 grain FMJBT in a new pulled AE5728A case chronos at 1100fps.

But with a Hornady 55gr FMJ-BT (#2267) it is only chronoing at 750ps...

So that's in the same gun with same powder charge and regardless of crimp, it's always 350fps slower 🤓

BEFORE I BLOW MY FACE OFF.BEING AN IDIOT... why are the Hornady 55gr running 350fps slower?

Disclaimer - don't copy my recipe, its at your risk and all that stuff

 

[HK SD9 Tactical]

Different metal construction of the projectile? Softer metals have less friction to overcome.

Got to tell you, I had a squib once in my PS90 and I had to hammer the projectile out of the barrel.

I can't specifically comment on the Hornady 55g as I only use the Sierra 55g for subs.

This is the reason they say if you change a single component in a published load, back off and rework the load.

Edited to add: Mike the projectiles to ensure the are both .224 I have come across projectiles that were listed as .224 and the were anywhere between .223 and .2245.

 

[levips90]

For low charge loads, Depending on how the powder fills/sits in the case effects the burn rate, but unless you’re doing something else different between loads I don’t know how you’d get that consistently.
Will be curious to see what people come up with.

 

[howdahpistol]

Answer = my chrono sucks !

I just tested on my friends chrono and all the Hornady bullets chrono'd around 1060 fps.

Sorry! 🤢

 

[HK SD9 Tactical]

What chrono?

 

[howdahpistol]

What chrono?

It's a Caldwell ballistic precision, although I think there might be an issue with my specific unit, because in general i think they are pretty well regarded.

 

[HK SD9 Tactical]

I have the Chrony Gama with the upgraded memory that will hold 1000 shots or 100X10 shot strings with the remote display.

Its had to find a low priced reliable unit and I won't spend $600 on a labradar model which has lots of less than good reviews. Maybe in 10 years it will be solid enough.

I looked at many chrony's when I first looked into them and Shooting Chrony seemed to be a more reliable one at the time. I am not that impressed with the reviews of the Cadwell but they make great brass catchers.

 

[Buffman]

Could have been the sun angle too? That really F"s with them. I had to make all new subs for my DBX since it's gas driven..