Vra QL manne vir Hulp met .243 win

[Quinna]

Middag almal, hoop almal het n lekker naweek

Is daar dalk iemand wat so bietjie tyd op hul hande het om my dalk te help met n node op n 243Win. Sal dit baie waardeer

Hier is die data

Cal. 243
Loop lente: 24,133
Loop twist: 1:8
Kruit: S365
Dop: Winchester
Dop H2O: 55,6 gr
TPL: 71,5
Punt: Noslert BT
Punt Gr: 90 gr
Primer: Winchester

Spoed op 38.5 gr
1. 2945
2. 2914
3, 2920
4. 2932

Lekker dag vir almal

[tripodmvr]

Chrony - MS?

[tripodmvr]

Chrony op 5m gebruik.

Laai 39,4gr vir spoed van 2995-15 vps. Druk by 50K psi. Volgende node is ver bo 60K weens die baie hoë brandtempo van die' lot 365.

[Quinna]

Baie dankie oom. Jammer vergeet om te se spoed is gemeet met MS. Gedink die spoed is bietjie laag. Dankie vir die moeite oom. Lekker naweek. Sal laat weet wat hy maak. Groete

[tripodmvr]

Die spoed is die teiken. Jy behoort naby te wees met 39,4gr

[Quinna]

Dankie oom sal hom so laai. Die spoed wat ek se is laag was myne wat ek gekry het nie oom sin nie. Ek het gedink die node sal naby 3000 le. Lekker aand oom en nogmal baie dankie vir oom se moeite

[tripodmvr]

Plesier, Quina. Mooi mik en skiet.

[Dale SH]

Quinna
What is your jump to the rifling.
The burn rate is excessively high and you havent reached 50 000 psi yet
I suspect that the bullet is in the rifling

[Quinna]

Hi dale I am .5mm from lands

[Dale SH]

You should not be generating a MV like that with 38.5 grains.
Yes the 243 is overbore and generates a high BRF factor, but this generally occurs when yhe pressure crosses the 50 000 psi mark.

How did you measure your jump ?
Your COL at 71.5mm is unusually long.
I would reduce your COL by 1.00mm and see what type of results you get.
If your burn rate does come down you could potentially reach the higher pressure accurate node

Which batch of S365 are you using ?

[Quinna]

I will come down more with the seat depth. I am using Lot 71.

[Dale SH]

OK.
Lot 71 was wild, I know from experience, however if you have the time reduce the COL by about 1.00mm and shoot the 38.5 grain load and lets compare the results.

[Quinna]

Sorry forgot to say. I use a case that i have cut open. I do this a couple of times and measure each one. Avarage it out. Then compare it to my lowest measurement. If it is more than .5 i use the lowest one. But i use the mag length -1mm as my tpl. Aways making sure it is less than the overall tpl

[Quinna]

Will do I will work up the load tomorrow and be on the range next week will let you know. Thanks for the feedback that is what i love about this forum people always willing to help

[Dale SH]

Im not a fan of the cut case method of measuring the COL.
The resistance of the bullet in the rifling causes it to stay behind a bit when you open the bolt and gives a false (longer than actual) COL reading.

[Quinna]

Hi Dale. My plans to get to the range did not go as i wanted. Any way. I did as you sugested and seated 1mm more. Can you please have a look. Inf to follow.

Case: Winchester
Bullet: Nosler BT 90gr
Primer: Winchester
H2O: 55.6
Twist: 1.8
Power S365 lot 71
Tpl. 70.5mm
Speed was taken with MS

38.5gr
1. 2927
2. 2922
3. 2915
4. 2913
5. 2909

39gr
1. 2928
2. 2933
3. 2943
4. 2931
5. 2923

The grouping of the second string was not bad. Will load a pic as soon as i can. The wind was also howling when these where shot

[Quinna]

Group shot with 39gr

[Dale SH]

Your burn rate has come down a bit with the longer jump.
Right now your accurate node sits at 40.3 grains for 3008fps at the muzzle.
49700 psi
Your next node is predicted to be over max pressure.
A slower batch of S365 will be better suited for your application

[Quinna]

Great thanks Dale. We are on the farm in 2 weeks will check then again. Thanks for the reply have a great week