JARACAL

Middag Manne

Kan uiteindelik begin laai vir die 270.

Kan iemand help met aanbeveling waar om te begin asb.

Rifle: Musgrave
Calibre: .270 win
Bullet: 130gr Hornady Interbond
Case: S&B
Case capacity: 70.31gr
Max TPL: 86mm
Propellant & batch: S365 / B91
Primer: CCI 250
Barrel length: 655mm
Twist rate: 1-10

By voorbaat dank.

Jan Dissel

https://www.somchemreload.com/search?c=8&f=36

Met jou langer loop kan jy so +50vps bo hul spoed verwag. Lot 91 is 'n bietjie stadiger as normaal, maar pasop met S365 synde dit 'n turbo effek kry wanneer die druk bo 50 000 psi gaan. Laai op in 1 gr inkremente en beskou die maks spoed op Somchem se aanbevelings as die maksimum vir jou langer loop.

Baie dankie Tripod

So... Ek het 2 ladings getoets die naweek.
Chrony 3m weg
Temp: 14
TPL: 85mm

52.5gr S365
3007
3014
3021
3020

53.5gr S365
3109
3086
3087
3104

Kan iemand my asb sê of ek op die regte spoor is?

By voorbaat dank

Jan Dissel

Ek vermoed die QL manne is in die jagveld....

Difficult one this as those chrony readings don't make sense.
+- 100 fps increase for 1 grain of powder ?

Try 53.0 grains and move the chrony back to 5 meters and then we can re-assess.

Dale SH wrote: Tue Jul 07, 2020 10:50 am Difficult one this as those chrony readings don't make sense.
+- 100 fps increase for 1 grain of powder ?

Try 53.0 grains and move the chrony back to 5 meters and then we can re-assess.

Thank you Dale

Maybe the "turbo effect" that Tripod mentions?

Some rain coming this weekend... Will maybe get a chance to chrony next weekend.

Regards

Jan

Jan Dissel wrote: Wed Jul 08, 2020 7:54 am

Dale SH wrote: Tue Jul 07, 2020 10:50 am Difficult one this as those chrony readings don't make sense.
+- 100 fps increase for 1 grain of powder ?

Try 53.0 grains and move the chrony back to 5 meters and then we can re-assess.

Thank you Dale

Maybe the "turbo effect" that Tripod mentions?

Some rain coming this weekend... Will maybe get a chance to chrony next weekend.

Regards

Jan

Morning Jan.
Could well be that your 270 has switched on its afterburner as your load and pressure are in the pressure band whereby the 270 has this effect.
I would still recommend that you move your chrony further away so we can eliminate the muzzle blast factor.

Judging by the weather forecast you guys in the Cape are in for a wild and wet week end.

That's what she said... ; )

Will do exactly like you said.

Jan Dissel wrote: Wed Jul 08, 2020 6:18 pm That's what she said... ; )

Will do exactly like you said.

Hahahhaha goeies!!

Goeie More

Hoop almal het 'n lekker naweek gehad.

Chrony was op 5m
Temp: 18
TPL: 85mm

Eerste groep na "cold shooter" skoot.

52gr S365
2982
2978
2953

Foto onder

Tweede group na 20min wag

53gr S365
3016
3028
3027

Foto onder

Begin lyk al nader na die waarheid. Wat sê die slim manne?

Jan

Jan Dissel.
Your MV and BRF are now more realistic.
Clearly you had a muzzle blast issue.
So let me ask you this.
How fast do you want to go ?
There is a higher node and lower node achievable.
Right now you closer to the lower node.
The potential higher node is at +-58000 psi and 3150 fps.

Hello Dale

Glad we got the muzzle blast issue out of the way.
I mostly use the rifle for hunting (Karoo) and occasional varminting.
Was hoping for speeds around the 3000 fps mark.
Can I maybe try both nodes and see which one gives best results? Maybe slower for hunting and faster for gongs/varminting I suppose only one load will be more practical.

To be honest I have no idea if the value of +-58000 psi is high or close to to high. Maybe you can guide me on that? Don't want to burn the barrel out just to get a few extra fps.

Regards

Jan

Your options are as follows:

Your predicament is that you currently sitting between Node 4 and 5 and this is the long jump node.

Lower node is predicted to be 51.3 grains for 2953 - 12 fps on the chrony at 5 meters.
46100 psi which would be considered border line for decent bullet expansion.
This is where most people are shooting their 270's accurately with a 600mm barrel.
You will have to asses how this works for you.
Check that your cases do not have a black ring that extends below the shoulder which will indicate poor bullet expansion/obturation.

Higher node as mentioned before is predicted to be 55.5 grains for 3154 fps - 12 fps on the chrony at 5 meters.
58700 psi.
This is a higher pressure node but still safe ( SAAMI max is 65000 psi)
I would load 55.0 grains to start with and see that you have not exceeded this velocity as I anticipate an increase in your burn rate as your pressure reaches the higher levels.
If 55.0 grains gives you +- 3120 fps on the chrony then continue to 55.5 grains and 3140 to 3150 fps on the chrony.

Check your accuracy around this node remembering their will be a substantial difference in felt recoil between the two options.

Thank You Dale

Will test the two loads over the weekend.

Thankyou so much for the help so far.

Jan

Good Morning Dale

Tested the two loads. Results as follows:

Chrony: 5m
Temp: 10
TPL: 85mm

51.3gr S365
2963
2938
2935

55gr S365
3154
3130
3157


Looks like I am a bit fast on the 55gr load?
Is it just me or does my groups stay more or less the same size with all my test loads? Was hoping to start seeing 0.5 MOA groups. It might be the shooter.

Any suggestions?

Jan

Jan, hierdie is 'n jaggeweer. Jy verwag akkuraatheid wat moontlik nie bereikbaar is nie. Met beide bostaande groepe het jy biltong in die huis. As jy die laer spoed gaan gebruik (dit is wat PMP hul 130gr koeëls laai) dan kan jy bietjie op en af kyk met 0,2gr inkremente om te sien waar die nodeband is. Miskien is daar dan 'n lading wat nog beter presteer.

Oom, die geweer het al 0.4moa groepe geskiet met S&B. So ek dink dis waarom hy maar wonder of voel daar is dalk meer potensiaal. Dalk was dit maar net spesiale ammo!

Your burn rate did increase more than expected with the 55.0 grain load so based on your current data my final recommendation would be 54.7 grains for 3144 - 11 fps on the chrony at 5 meters = 3133 fps average
The above for the highest achievable node.

And

51.4 grains for 2950 - 13 fps on the chrony at 5 meters = 2937 fps average
The above for the lower node.

I must add that it looks like you getting a flyer which generally indicates shooter error, barrel heating up (shooting too quickly between shots) or barrel touching the stock.

tripodmvr wrote: Mon Jul 27, 2020 10:16 am Jan, hierdie is 'n jaggeweer. Jy verwag akkuraatheid wat moontlik nie bereikbaar is nie. Met beide bostaande groepe het jy biltong in die huis. As jy die laer spoed gaan gebruik (dit is wat PMP hul 130gr koeëls laai) dan kan jy bietjie op en af kyk met 0,2gr inkremente om te sien waar die nodeband is. Miskien is daar dan 'n lading wat nog beter presteer.

Middag oom Tripod

Dankie vir die raad. Ek wil defnitief nog bietjie op en af toets en kyk wat met groepe gebeur.
Ek stem 100% saam en wil nie ondankbaar klink die. Dale doen 'n uitmintende goeie werk. Ek kan al heeltemal tevrede wees met huidige resultate. Die geweer skiet eintlik heel goed met amper enige ammunisie. Soos 'n 270 moet

Hier is 'n paar fotos wat ek in die verlede met rak ammunisie reg gekry het en soos FIGJAM sê waar die oorsprong vir my hoë verwagtinge vandaan kom.
Ek moet wel noem dat ek hier my 'n "silencer" geskiet het en ek dink tog die maak die lewe so bietjie maklikker as dit by die skoot trek kom. Kry dit natuurlik ook nie keer na keer reg nie.

PMP Pro Amm 150gr PMP 130gr (bruin boks) S&B 130gr

Dale SH wrote: Mon Jul 27, 2020 5:55 pm Your burn rate did increase more than expected with the 55.0 grain load so based on your current data my final recommendation would be 54.7 grains for 3144 - 11 fps on the chrony at 5 meters = 3133 fps average
The above for the highest achievable node.

And

51.4 grains for 2950 - 13 fps on the chrony at 5 meters = 2937 fps average
The above for the lower node.

I must add that it looks like you getting a flyer which generally indicates shooter error, barrel heating up (shooting too quickly between shots) or barrel touching the stock.

Thank You Dale

Will load up your recommendations and test as soon as possible. I must agree with you the flyers is constant in all of my groups... Maybe a slight flinch from not shooting with silencer.

Thanks again for all your great help.

Regards

Jan

Jan Dissel wrote: Mon Jul 27, 2020 7:24 pm

Dale SH wrote: Mon Jul 27, 2020 5:55 pm Your burn rate did increase more than expected with the 55.0 grain load so based on your current data my final recommendation would be 54.7 grains for 3144 - 11 fps on the chrony at 5 meters = 3133 fps average
The above for the highest achievable node.

And

51.4 grains for 2950 - 13 fps on the chrony at 5 meters = 2937 fps average
The above for the lower node.

I must add that it looks like you getting a flyer which generally indicates shooter error, barrel heating up (shooting too quickly between shots) or barrel touching the stock.

Thank You Dale

Will load up your recommendations and test as soon as possible. I must agree with you the flyers is constant in all of my groups... Maybe a slight flinch from not shooting with silencer.

Thanks again for all your great help.

Regards

Jan

Jan.

Now that we have finalized your loads and we know that they are safe and should be accurate, shoot them with and without your silencer and see if your grouping improves.
Just make sure your reloading technique is constant and repetitive.

Good day Dale

Hope all is well. Just want to share the interesting results this weekend after shooting your last recommendations. Four things that must be considered.
1. I must admit I was in 'n bit of a hurry.
2. It was very cold after the snow we had in the area. (slower speeds than expected)
3. I cleaned my barrel since I last went shooting.(carbon only) (4 weeks ago)
4. New scope


Tested the two loads after cold bore shot. Results as follows:

Chrony: 5m
Temp: 5 - 8
TPL: 85mm

51.4gr S365 (Without Silencer)
2880
2907
2893

51.4gr S365 (With Silencer)
2887
2897
2950
Amazing how my point of impact shifted 6 inches down. In other words I lose 24 clicks in elevation just by using my silencer...?

54.7gr S365 (With Silencer)
3064
3091
3075

I want to stick with the slower node.

I still want to play with the loads like Tripod suggested (0.2gr increments) and maybe also with seating depth and see what happens.



Regards

Jan

Not bad for a 270 and a shooter in a hurry with a clean barrel
You can load a few tenths of a grain up and down and play with your COL to your hearts content.
Try batching your cases by H20 volume, focus on neck tension and load BTO with a comparator gauge.

Thanks Dale

I don't have all the tools yet.

Quick question:
Are you satisfied with the speeds of the 51.4gr load? If I understood you correct the node speed should be at 2937fps? (@ 5m chrony)