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Forum Index > Rifles general discussion > Reverse Engineering a factory load?

Reverse Engineering a factory load?

07 Sep 2019
@ 01:16 am (GMT)

Shawn Bevins

I have been helping a friend try to reload for his Savage 270 Win. He was using factory loads and getting very good groups but at $54.50 a box he wanted something cheaper.

I figured, 1.) the rifle is capable, 2.) I can get the same bullet (Nosler 150 gr Accubond) & 3.) I have a known velocity that is accurate to work with (his rifle is getting an avg 2775 fps with a 24" barrel).

Well, life isn't so simple. Loading to match factory is interesting. Pressure signs on factory brass show a flattened primer. Reloads are once fired brass. Pulled powder appears to be H4350 but at the weight of recovered powder, velocity is way under factory loads. (Special powder?) OAL was set the same.

I had IMR4350 on hand and H4350, H4831, IMR4895. H4831 looked the most promising. We tried CCI and Winchester LR primers. Even got different dies. Run out was minimal with his Lee dies.

I have watched him reload.. He is capable and consistent. My guess is try different powders & primers. Increase the neck tension too.


Anyone have any suggestions?











Replies

07 Sep 2019
@ 03:12 am (GMT)

Robert McLean

Re: Reverse Engineering a factory load?
That is hard. There are so many variables between factory and reload. First the brass is not fire formed and from a batch that you have no access to. So I would think that you would have to use new cases every time. The powder and primer is well, who knows what. Proprietary cases, powder, primers, tools and then just batch can mean alot. Neck tension, crimp and on and on...

Did you try to just pull the bullet and then reseat a new bullet to see if you could even get close with just that step? Then maybe change out powder and seat, leaving the primer in place. One bite at a time.

Sorry, i just don't see it. I think it is a rabbit hole. Maybe good fun to try but maybe a dangerous side to this game too.

My off the shelf 7mm 139 hornady rounds that I talk about in my Sendero post are great but I take that as just a sign that I can do better. Rounds I build are more in every way. I am confident that I can take my .6 groups with these factory rounds and turn them into .4 groups at least with what I build.
07 Sep 2019
@ 04:15 am (GMT)

Paul Leverman

Re: Reverse Engineering a factory load?
Have to agree with Robert. If you have an accurate barrel and action with a factory load, find the same results with reloads. Start at step one and go.
07 Sep 2019
@ 04:16 am (GMT)

Paul Leverman

Re: Reverse Engineering a factory load?
Have to agree with Robert. If you have an accurate barrel and action with a factory load, find the same results with reloads. Start at step one and go.
07 Sep 2019
@ 06:11 am (GMT)

Luis Vazquez

Re: Reverse Engineering a factory load?
You can try RL19, it worked on my 7mm Rem Mag with 160gr and 162 gr bullets when other powders wouldn't. Also maybe try Federal primers.

I like the bullets going at max speeds but not at the cost of accuracy, I have some loads that will be 50 or 100 fps slower than max loads but they group sub half MOA so you might need to back down a bit from the max amd work your way up like any other load development.

Hope this helps

Luis
07 Sep 2019
@ 06:14 am (GMT)

Shawn Bevins

Re: Reverse Engineering a factory load?
I am at the point of starting from scratch... I suspect proprietary powder. He is taking the gun out to the western part of the US for elk and mule deer. He would shoot the $$$ ammo while there. He wanted to get an accurate reload to practice with.
07 Sep 2019
@ 06:40 am (GMT)

Luis Vazquez

Re: Reverse Engineering a factory load?
You're better off, I know multiple people have tried the reverse engineering and it hasn't worked, provably as you mentioned due to the proprietary powders. Especially with the superformance from Hornady, the one available is not the same as the one used on their factory ammo.

Hope it works out for you and your friend

Luis
08 Sep 2019
@ 01:54 pm (GMT)

Mike Davis

Re: Reverse Engineering a factory load?
well you arent completely sunk and I think you arent off track too much.
#1 you know a projectile,seating depth and velocity rifle likes.
so you have a really great starting point. personally I would take one of them factory loads and use it to set up your bullet seating die and find book load that looks to give similar velocity and just see what happens.
I did just that for years with an old school silvertip load,the seating die hits at point on the curve (cant spell the oglive word) so it SHOULD be similar distance off rifling with similar shaped projectile.
my old .270 isnt fussy or maybe its me that isnt...you can put ANY load through it into a playing card sized compisite group at hundred yards...a good load will go sub inch.... dont try to reinvent the wheel...go with what you know and fudge the rest,the rifle mightnt mind,you wont know till you try. the deer sure wont know the difference.
13 Sep 2019
@ 02:54 pm (GMT)

Warwick Marflitt

Re: Reverse Engineering a factory load?
https://www.ballisticstudies.com/Knowledgebase/.270+Winchester.html

Read this and take from it what you will. Nathans Knowledgebase is full of good sound practical knowledge.........
Why reverse engineer when you can do Precise custom load development for the rifle with its COAL and fire formed cases used to make Blueprint ammo?
 

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