Powder Velocity Advice!

[BMG]

Hi All
I would like to use Varget in my .243. I am using 90 grain Swift Scirocco II bullets in Lapua cases with Federal Match Primers. My rifle has a 26' match grade stainless barrel.

Hodgdon indicate max load should be 36.5gr with 3106 velocity,24' barrel).
Speer manual indicates max load 38.0gr with 3094 velocity,22' barrel).

I am in the process of doing a ladder test to aid my ammunition development and would like some advice on how much powder I can use. My results are as follows:

36.2gr Varget = 3023 vel.
36.5gr,Max on Hodgdon website) Varget = 3032 vel,no pressure signs visible).
36.8gr Varget = 3054 vel,again no pressure signs).

While I had my chronograph set up I tried 3 rounds using SAKO 90 grain hunting ammunition. My finding was:

1st shot = 3153 vel.
2nd shot = 3169 vel.
3rd shot = 3105 vel.

I have no idea what powder the company uses or how much?

Does this mean I can steadily increase the Varget grains, supposedly well in access of the maximum load indicated on the Hodgdon website,I am favouring this website over the Speer manual data because Hodgdon used a 24' barrel as opposed to a 22' used for the Speer data) so I can reach 3100'ish to match the SAKO ammunition, or will Varget not be able to attain this velocity within the safety margins of my rifle? I know you guys might say slowly increase and find out. If this is the case how much of an incresae should I use, .1 grain at a time over the 36.8 starting point,already .3 grain more than max), or a different amount?

Look forward to hearing from you guys.

Kind regards

BMG

 

[JRinCo]

Reloading manuals are a must, but they are only guidelines. There are too many variables. In this case Hodgdon lists a bullet labeled only as spr sp, which I take to mean spitzer soft point. Exactly which brand and model who knows, but it's important. You are developing loads for a Scirocco II, which has a really long bearing surface and a thicker jacket than most soft point bullets, which in turn will act differently. Those two factors will cause more pressure and possibly less velocity potential than other bullets.

Just learn to rely on your own observations in regard to pressure. Manuals are great for a ball park starting place and will give you some reasonable assumptions as to what velocity is possible, when all of the components are similar.

 

[M700]

Don't know if you've already checked it out, but there is a tremendous amount of information about the .243 Win right here in this article: http://www.6mmbr.com/243Win.html

Also - I'd read 'spr sp' as meaning the Speer soft point, but who knows?

As JRinCo mentioned, the manuals are guidelines. It does get a little frustrating when maximum in one manual is considerably different from maximum in another manual. I'd tend to think that since Speer published 38 grains, you could safely work towards that, but I wouldn't push it, since you're already at Hodgdon's max. Interesting eh?

Also - just something that I've become more aware of over the years, a hundred fps one way or the other really isn't that big a deal, particularly in the field. Your rifle is already shooting about 100 fps short of the factory ammo you tried, and that's pretty good. I'd be looking for a good-shooting load somewhere between 3000 - 3100 fps, or maybe a little more.

It will be interesting to see what kind of velocity you get if you try that 38 grain load from your longish barrel! Might be pretty impressive...

Regards, Guy

 

[BMG]

Hi JRinCo and M700

Thank you very much for your advice. One part of my question hasn't been answered and I was wondering if you could help. The question being how much shall I increase my loads by for each round. Should I increase by .1 of a grain or more, if so how much?

Kind regards

Brian

 

[JRinCo]

As nearly as I can determine from the manuals that I have, you are in the zone at 36.8 gr. of Varget.

I have no idea what equipment that you are using. If it were me and my equipment, I would look for a hot day, if there are any left in your area. I would load 3 rounds with 2/10 of a grain more powder than the last charge and fire them over the chronograph. I would pay very close attention to stiffness in bolt lift and closely look at each case head for any sign of shinny mark on them. I doubt that you can go very much higher in charge weight with Varget.

I suspect that SAKO would most likely use one of the Vithavouri powders in their loaded ammo.
Good Luck

 

[BMG]

Hi JRinCo

Because I have never loaded over the max indicated in the manuals before I was unsure of how much I should increase each load by, so your advice is greatly appreciated. I will increase my loads by .2 grains at a time and check for pressure signs.

Kind regards

Brian

 

[JRinCo]

Let us know what your results are.
JR