Barnes TTSX 150gr

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squeek
Posts: 80
Joined: Mon Dec 29, 2014 6:03 pm
Location: Netherlands

Barnes TTSX 150gr

Postby squeek » Thu Jan 01, 2015 4:47 pm

Bullet: Barnes TTSX 150gr
Powder type: Vihtavuori N140
Powder weight: 45,5gr
Case type: Lapua Palma
Case lenght: 51,08
Primer: cci 400
COAL: 72,25mm
Barrel length: 58cm
Bullet speed: 823m/s
Group size: /

Lower the charge for 10% and go up carefully while watching for signs of pressure!
YOU ACCEPT THE LOAD ON YOUR OWN RISK!


I hunt with 45,5grs N140 behind a 150grs Barnes ttsx.

I'm using Lapua palma cases (51,08mm) and CCI 400 small rifle primers. Cartridge over all length is 72,25mm, about the longest that will fit in the blaser magazine.

The blaser barrel is 52cm and has a 1:11 twist or so i'm told.

Quickload promises 855 meters per second but the Magnetospeed says 823 m/s. Don't know which one is the truth.

At 100 meters all shots converge in a ragged hole.


Works for me, but may be useless or dangerous for you, so don't try without consideration

dchamp
Posts: 110
Joined: Thu Dec 11, 2014 2:51 am
Location: California

Re: .308 winchester

Postby dchamp » Fri Jan 02, 2015 2:26 am

Although QL can be very accurate, there are variables, some controllable like propellant data that can change with different lot's, some not like primers. Also, QL bases their projections on standards listed from Saami or CIP for chamber dimensions etc.

Another thing is to measure your barrel length from the face of your bolt and not by what Blaser list. I bet it's slightly shorter. While QL may show your pressure to be on the high side if it works for you and you have determined it safe in your rifle then all is good. :)
TO RIDE, SHOOT STRAIGHT & SPEAK THE TRUTH - COL JEFF COOPER

trazman
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Joined: Tue Dec 09, 2014 7:45 pm
Location: Koper/Slovenia

Re: .308 winchester

Postby trazman » Fri Jan 02, 2015 10:42 am

You are right Dchamp, bbls are 2cm shorter because of the bolt head closeing in... So the standard barrel that is published 58cm is actually 56cm and this should be used for QL data...

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squeek
Posts: 80
Joined: Mon Dec 29, 2014 6:03 pm
Location: Netherlands

Re: .308 winchester

Postby squeek » Fri Jan 02, 2015 1:24 pm

Ah? I should measure from the boltface? didn't know that.

Until now I measure from the start of the rifling, where the bullet takes off so to speak.

I just measured the length a cleaning rod enters on a closed bolt and that's 58cm give or take a few millimeters.

Just learning already :mrgreen: my day is not lost.

User avatar
squeek
Posts: 80
Joined: Mon Dec 29, 2014 6:03 pm
Location: Netherlands

Re: Barnes TTSX 150gr

Postby squeek » Fri Jun 08, 2018 8:07 pm

Hi all,

I do not longer use the load mentioned above due to the fact that I can't repeat the calculation in QL. It seems this load is too high in pressure, if I recalculate it now I get 888m/sec and not 855 which I do not understand.

I have never had overpressure signs but QL makes me nervous...

Stay safe!

Squeek


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