Reverse Engineering a Factory Load

csl

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Does anyone know a way to reverse engineer a factory load? Obviously it's easy enough to copy the dimensions and choose a similar bullet but I guess it's the powder that's the tricky bit!

My .243 really likes 100gr Federal powershock...

IMAG0001 (Large).jpg

but once my stock is run down I'm planning to move onto reloading for it. I have a similar issue with my .223 - it loves Sako 50gr 'Arrowhead'.

I was wondering if there is any information out there with regards to what powders are most similar to what factory loads to assist with choosing a suitable powder. Then it would just be a question of working up the loads from minimum in the usual way.

Suggestions?

Or is trying to short-cut the normal process an exercise in futility?

thanks,

Alex
 
Alex,

My T3 Lite .243 liked Federal Powershok also, 100gr bullets.

When I reloaded for it, I was using 36gr of H380, I was getting the same PIO as Federals, which was very convienent.

TJ
 
Does anyone know a way to reverse engineer a factory load?
I have a similar issue with my .223 - it loves Sako 50gr 'Arrowhead'.

Alex

Alex, Sako used to publish their load data on't net. I don't know if they still do.
 
Its very easy even without a chronograph.
Find the published MV for the load, try the side of the box, failing that the manufacturers website.
Then use a good reloading program, I'm still using Sierra Infinity 5 and iuts good.
Select a bullet (you can try different makes with infinity) and look up the same MV for bullet weight.
Then load some samples and shoot them against a test group of factory from the same rifle. all being well they should group the same, same poi etc. If not then try slightly warmer or slower loads until you find the sweet spot!
I shoot these test groups on a 4 foot board and label each group and take a digital photo with a ruler across the group. save to hard drive and hey presto go home and do the maths in the warm.
I managed to find a 125 grain .303 load that had the same poi as my Norma 150 grain factory loads at 100 yards. Job done.
 
With regard to the .223 Sako list the load as- 50Grn Arrowhead 21.6 grns of Vhitavouri N120. The arrowhead bullet is really a Nosler ballistic tip.
 
Thanks BB, I would do that as part of a normal load development, the problem is that there must be many different permutations of loads that would give the same muzzle velocity with different ingredients, maybe the same average POI, but surely not the same grouping?

If you have a factory load that you know works well (as in groups tightly) I am trying to avoid having to shoot loads of groups to find an equivalent. For example, now that I know the recipe for the .223 sako load I can choose an identical bullet, seat it the same as the factory load, choose the same powder, then start at book minimum (which is 21.2 for vit 120) for safety and work towards 21.6gr knowing that I *should* hit the sweet spot on or around 21.6gr.

In theory..... :-|
 
But either way shooting the groups and recording them is a good thing, as you are already working up to max then you would be able to take them home and re do the calcs later if necessary!
 
In theory..... :-|

In "The ABC's of Reloading" there is a whole chapter called "Cloning Factory Ammo". It's a fascinating article, the conclusion of which is that you can't! You can duplicate components - well, almost - but at the end of the day you will still end up tweaking your own load for best results. My take on it is that, whilst you can almost duplicate the components (case, powder, bullet, primer), the lack of production-scale machinery affects the level of consistency that can be achieved in the resulting rounds. Inevitably this means that you will end up producing handloads, not factory loads.....if that makes sense??

willie_gunn
 
Yes it does but with as much consistency if not more than factory ammo, the holy grail of the handloader for many years, improve upon the factory offerings at a better price!
 
Yes, that's certainly the aim - to produce a consistent round that provides accuracy and performance at least on a par with, if not significantly better than, a factory round.

I've left out the "better price" bit, as none of us seem to factor in the cost of all the hours we spend working up the loads, testing and refining them...;) Nor indeed all the kit, gizmos and gee-gaws that reloading seems to spawn (he says, having just bought another set of electronic scales).

When it comes to reloading, the accuracy vs cost graph is a great example of the Law of Diminishing Returns :D

willie_gunn
 
Not forgetting the adage, "Eventually it will work out cheaper!"
I find that I like a factory load, then reload to match the poi. Then I'll find a cheaper factory load and use that for the clients in the estate rifles. After that its down hill but at least I'm not reloading to shoot and then deliberately shooting them all off so I can reload again. Pistol was like that!
 
Alex, most factory ammo is normally loaded very near the max safe powder load, cases as a norm 003" smaller in dia, bullets seated well back, so anything hand loaded will usually out perform factory ammo, so once fired cases (from your rifle) as near perfect a fit as you can get, then it's just a case of trying bullet seating that suits your particular rifle to find that "sweet spot",ie. 030", 015",005" away from the rifling, or even touching the rifling, just as long as you start with minimum safe powder loads and work up, you might even find a lighter load of powder will be quite a bit more accurate....callie
 
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