JARACAL

My buurman het sy kluis skoon gemaak toe kom hy op die 270 af.Die laaste keer wat hy winkel toe was het hy met n Bles Bridges lp by die huis aangekom want hy was te skaam om vir 270 ammunisie te vra.Nou wil hy self laai en vra raad asb.

Tpl 83
Kamer. 89
Loop. 24.2"
Doplengte. 64.5
Punte. Hornady sst 140
Spoed 48.5g. 2779.33 crono 5m
49.5. 2877.67
50.5. 2893.67
Volume. 71.2 g.
S355 lot 010

DD

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driepoot sal jou beslis help!!!
Groetnis
Gert

Your 48.5 grain load and 49.0 grain load give the same speed !!!
You sure ?

Dale SH wrote:Your 48.5 grain load and 49.0 grain load give the same speed !!!
You sure ?

I lost my spectacles but I am sure they were not the same . I don't recall a 49gr load.

Spoed 48.5g. 2779.33 crono 5m
49.5. 2877.67


DD

You right my mistake.
Anyway as it stands S355 is too fast burning for a 270 and 140 grain bullet.

Difficult one as it always is with a 270.
Look what happened between 48.5 and 49.5 grains
100 fps increase as you crossed the pressure threshold whereby the overbore calibers and especially the 243 and 270 start acting stupid.
Then an additional 1 grain between 49.5 and 50.5 gives you 16 fps as youve reached saturation point.

I am going to recommend a 49.0 grain load and look for 2865 -15 fps on the chrony

You neighbour with the dusty safe queen guns would be better off with S365 if you can find some.

Dale SH wrote:You right my mistake.
Anyway as it stands S355 is too fast burning for a 270 and 140 grain bullet.

Difficult one as it always is with a 270.
Look what happened between 48.5 and 49.5 grains
100 fps increase as you crossed the pressure threshold whereby the overbore calibers and especially the 243 and 270 start acting stupid.
Then an additional 1 grain between 49.5 and 50.5 gives you 16 fps as youve reached saturation point.

I am going to recommend a 49.0 grain load and look for 2865 -15 fps on the chrony

You neighbour with the dusty safe queen guns would be better off with S365 if you can find some.

Thanks Dale wil pass the info on.

DD

The neighbor got some s 365 lot 86 and tried some behind 140gr sst at tpl 85mm with case volume of 71.2grh2o barrel 24.2"
.
49gr 2643fps
50gr 2686fps
51gr 2725fps good group ,Crony at 5m

There is room to spare in the case wil he reach 2900fps with these components ?

DD

DD

Your neighbours 270 is idling at 41000 psi with his 51.0 grain load and his burn rate will increase substantially as he crosses the 50 000 psi mark.
My suggestion would be to load a 53.0 and 54.0 grain load and see where we at with the MV.
Shoot the 53.0 grain load first and if you near 2930 - 2950 fps then stop and dont shoot the 54.0 grain load.
Give us the data and we can fine tune it from there.

But yes he should comfortably reach 2900 fps.
If the Burn rate increases as I expect it to, there should a safe node at between 2910 and 2950 fps.

Dale SH wrote:DD

Your neighbours 270 is idling at 41000 psi with his 51.0 grain load and his burn rate will increase substantially as he crosses the 50 000 psi mark.
My suggestion would be to load a 53.0 and 54.0 grain load and see where we at with the MV.
Shoot the 53.0 grain load first and if you near 2930 - 2950 fps then stop and dont shoot the 54.0 grain load.
Give us the data and we can fine tune it from there.

But yes he should comfortably reach 2900 fps.
If the Burn rate increases as I expect it to, there should a safe node at between 2910 and 2950 fps.

Thank you Dale.

DD