Trying to Match Factory Ammo

[HARV6]

So Ive got a 25-06 that shoots factory loaded 115 Partitions from Federal into EXCELLENT groups. Federal's website says they're coming out at 3030fps, but I've not checked that with my chronograph. So I went and bought some of the 115 Partitions. QuickLoad tells me I can safely take them over 3200fps with Retumbo, and I did so without finding any pressure signs. I used 6 different 1-grain increments to get there (55, 56, 57 etc), but accuracy wasn't great and once above 3075fps it was terrible. The load data on Nosler's website also indicates that they found best accuracy with this bullet, powder, and barrel length at 3012fps. With rifle season nearing, and not a whole lot of time, my option are.

1. Load up another 24 rounds at 1 grain increments (55.5, 56.5, 57.5 etc)
2. Load fewer increments, but test more around the 3030fps mark
3. Try a different powder.

Just tryin to decide what my last effort should be to get a great hunting load before the season starts.

 

[jwrowland77]

Do a workup using .3gr increments. You'll find a load. From reading, it looked like you did a lot of jumping around and could have very easily jumped right over the load that fits your barrel.

 

[jimbeaux82]

First off - go and buy a Chrono. best $100 you will ever spend in reloading. Chrono the Federal factory load thru your rifle. What is printed on the box may or may not be what you are getting from your rifle. Second, measure the OAL of the factory loads since your rifle seems to like that OAL. Third, pull the bullet on 3 cartridges and measure the charge weight and look at the powder to get an idea of what type it is, stick, ball, etc. Then start trying to duplicate the factory load. You already have an AOL that your rifle likes which is a great start. With a chrono you will then have the velocity that your rifle likes. So all that leaves you with is trying to duplicate the powder type and charge weight. While the factory powders may be slightly different from our canister powders, by matching the type and charge weight (with caution) you should be able to duplicate the Federal factory load that your rifle likes. I have had great success in the past following this method.

Good luck

Jimbeaux

 

[Captcurt]

+1 on the Chrony Purchase.

Jimbeaux is right on with the Chrony suggestion. Factory ballistic are usually 100-200fps too high. They sometimes use pressure barrels or longer factory barrel that are not the norm. The only factory loads that have come close to published speeds that I have checked have been Weatherby.

 

[ironworkerwill]

You could pull one of the factory rounds to see if it's stick or ball, weigh the charge, then cross-reference that to the MV of other powder. You won't likely find the exact powder, but a different close match.

 

[HARV6]

Thanks, I mentioned that I already do have a chronograph, and that I just haven't had a chance to shoot that specific factory load over it yet. I did steal the OAL of the factory rounds though and have been using that. Just trying to see where you guys think I'll likely find success a little sooner to save a trip or two to the range. Or maybe to get a little more trigger time with the right load before the season starts.

 

[gamestalker]

First off, I don't shoot factory, this is because I've yet to shoot any factory that could out shoot a properly worked up reload. In other words, why not forget about trying to duplicate the factory stuff, and just simplify the process and do a normal load development.

The way I go about finding tack driver loads for any of my rifles, is as follows.

I first start with the bullet seated up to the lands, then I work my powder charge up at that oal.. Once I find the powder charge, and if I'm not already getting excellent groups, I then begin decreasing the oal in .005"-.010" increments until I find the most accurate oal.. If at that most accurate oal groups aren't what I'm expecting or happy with, I then begin tweaking the powder charge in .3 gr. increments. This often means tweaking it down since I'm often at the upper end of the table at this point in time.

GS

 

[Otto]

Even if you transferred the powder from a pulled factory round to your own case you'd likely get no better results. Brass condition, prep and neck tension has more to do with accuracy than most people think.

 

[gamestalker]

^^^

Weighing brass, consistency of neck tension, using formed brass, these are some of the most important keys to shooting a ragged hole, not what the factory stuff is made of.

GS

 

[rsrocket1]

In many instances factory powder is not retail cannister powder so a certain weight of what looks like a certain powder may not perform like the retail counterpart.

Your first goal in working up a load to match a desired factory load is to chronograph what is coming out of your gun with the "good" factory loads. The next thing to do is to try to match the MV's and see if it matches the accuracy.

I've done that with .223 loads out of my AR and when my loads matched the velocities of the facotry loads I liked, the groups were identical. I did have to select the same headstamp brass, not necessarily the identical brand name, but just keeping consistent by using brass with he same headstamp helped keep consistent MV's which also helpt with the goupings.