Load Development: How to?

[Trent]

:eagerness: Being a stickler for both attention to detail as well as "math in real life," I would like to gently suggest that .4 grains is one percent (not 10 %) of 40 grains. The same is true for .2 grains relative to 20 grains. (10%, on the other hand, is about the difference between many published minimum and maximum loads.)

:focus: I do not mean to take away from the main point of Trent's post (with which I agree wholeheartedly): the exact variation between powder loads during load development depends on the amount of powder being used. It wood be rather time consuming to try and develop a 50 caliber load by changing powder loads by 0.1 grain increments.


DOH!! You are right. Edited my original post to fix my typo!

[handsomerob]

There is lots of good information here. You've all given me plenty to work with. Hopefully I will have time tonight to load some rounds. I will start at .01 of of the lands and work through the powder at i think .3 grns. I'll try to make it to the range this weekend.

[handsomerob]

Okay, I finally got some free time today and loaded about 7 different weights of IMR 4895. I have two sets of 3 shot groups. There will be more but that's all the cases I had the were close in weight. I found my distance from the base to the lands and also the my OAL with Sierra Matchkings 168gr. I went with these because the Federal gold medal match are the best factory ammo that my gun likes.

I noticed that some of the OAL's would move even though I didn't touch my bullet seater setting. I measured some of the bullets and they were fairly consistent but I can see that the difference in bullet lengths would through off my OAL. All that is fine by me because I realize the tip of the bullet isn't what touches the lands. I'm wondering if my base to ogive is off too? And whats the best way to measure that. I just set my caliber to .300 and locked it then made a mark around my bullet. I realize though that's not the most accurate way to measure it plus I don't want to mark all of my bullets that way.

I saw a couple people mention a bullet comparator. So I looked that up. It seems to be what I am looking for. You guys agree? Any recommendations of which maker to use? All I could find was a Hornady and Sinclair. Also thanks John_M for the links. I wasn't expecting the differences in OAL. I started reloading with a Lee Classic Loader and Nosler Ballistic Tips. Those OAL's were very consistent. I got a bench set-up from my mother-in-law for Christmas. I am learning how to use that set up accurately.

[fgw_in_fla]

I don't know if you can get every cartridge exactly the same COL. I believe you'll find slight variations in bullet OAL, slight variations in the diameter at the ogive. They're not 100% perfect.
Are you shooting competition?
ALthough I don't shoot sanctioned competition, I still try to be as exact (exact: see OCD) as possible. I find after going thru hours of trying to make ammo a near perfect as possible for what I have to use, I still see variations in COL by sometimes as much as .005" to .007".
And after all is said & done, they still print some incredibly tight groups. So long as I'm "on" that day.

If you're finding minor variations in your COL or OAL to ogive, I think you'll be OK.... Give them a try & see how they perform. If you're still in developement, I really don't think minor variation in COL will impact your OCW test. After you find out what actual charge you'll be getting best accuracy from, then you can be concerned about length. Maybe some better brass? Find out which cases give the most consistant OAL and reuse only those? I think there's a few ways to overcome the "irregular COL syndrome".
Some of our resident BR guys will no doubt have more info for you.

Frank in Fla

[fgw_in_fla]

Hey HansomeRob - Something else comes to mind here. I just re-read your original post & it seems like you're just starting your OCW test. I don't think a few thousandths on your COL is critical right now. I think you'd be better off finding that accuracy node or sweet spot first. Then we can all try real hard to totally confuse you with neck tension & exact COL & such.

I think if you focus on the preliminary stuff, you stand a better chance of learning as you progress, too. You're going to find things like neck tension can drive you batty. I didn't pay alot of attention to neck tension when I first started reloading. Once I was able to grasp the necessity of consistant neck tension, along with consistant OAL, charge weight, etc.... My grouping tightened up quite a bit. I believe I stopped crimping right about the same time, too...

Slow & steady. Be consistant & you'll do fine. Good luck -

Frank in Fla

[handsomerob]

It was a pretty nice day and finally got some free time. I'd have to say I did well and learned some things. I wasn't able to go through the whole scale of powder charges. I went from 41 grains to 43 grains in .4 grain increments. I'll probably do the 43.4 to 45.4 grains next week.

Savage Axis 308 Win. - Lighten trigger to 3lbs, used a washer to clean up side to side slop in the trigger as well, and added some weight to the hollow part of the buttstock.
Bullets - 168 gr Sierra Matchking BTHP seated .010" off the lands. COL 2.852"
Powder - IMR 4985 measured with digital Frankford Arsenal scale
Remington Brass
CCI Primers

Shot off a Bi-pod with a bag rest in the rear. Before shooting I cleaned with a bore snake and shot 3 fouler shots before starting grouping.

41.8 gr - http://i258.photobucket.com/albums/hh273/handsomemanrob/TgtGfx418.jpg

42.2 gr - http://i258.photobucket.com/albums/hh273/handsomemanrob/TgtGfx422.jpg

42.6 gr - http://i258.photobucket.com/albums/hh273/handsomemanrob/TgtGfx426.jpg

43 gr - http://i258.photobucket.com/albums/hh273/handsomemanrob/TgtGfx43.jpg

I put links because my targets were ones I printed and scanned in so they are pretty big. 42.2 grains were my best grouping ever at .505 MOA which is awesome. That was better than what I could do with Federal Gold Medal Match. That said I think I can do better. I need to work on my shooting technique. I'm also thinking about replacing the Bushnell Scope that came with it. This weekend I will start my project of building a laminate stock for it. The stock one from Savage is way too flexible for my tastes. After seeing what Bob Fortier can do I gotta give it a try. I'll be sure to post updates. Thanks for all of your help.

[supergolfer18]

I would look in the 41.8-42.2 area. Both these appear to have very similar POI. May even want to drop down to 41.4 and go back up to 42.2 to verify. Also did you see any pressure signs at 43gr? Hodgdon lists higher charge as being max

IIRC those bullets like a "jump" to the lands not that close to them. But like JIF posted initial test just establish max pressure then look for the 3 groups that have same POI then pick the middle charge. Then you can play with seating depth to tighten things up

Good luck

[devildogandboy]

don't know how much reading you like, but if you have some tiime, this is a good read! i haven't used it yet, but will on my next load. sounds good!
http://optimalchargeweight.embarqspace.com/#/ocw-instructions/4529817134

[supergolfer18]

devildogandboy: that is what I have been using and it is good load workup I believe. You should give it a try

[handsomerob]

don't know how much reading you like, but if you have some tiime, this is a good read! i haven't used it yet, but will on my next load. sounds good!
http://optimalchargeweight.embarqspace.com/#/ocw-instructions/4529817134

I have had this bookmarked for a while now and have given it a look over every now and then.


I would look in the 41.8-42.2 area. Both these appear to have very similar POI. May even want to drop down to 41.4 and go back up to 42.2 to verify. Also did you see any pressure signs at 43gr? Hodgdon lists higher charge as being max

IIRC those bullets like a "jump" to the lands not that close to them. But like JIF posted initial test just establish max pressure then look for the 3 groups that have same POI then pick the middle charge. Then you can play with seating depth to tighten things up

Good luck

I'm using IMR 4985 which is listed as 45.4C as max. Not sure I you If you were looking at H4895 which is listed at 43.5 as max. I am thinking about the 41.8 to 42.2 area. I might even go 41.8 to 42.4 in .2 gr increments and see what I find out. I haven't been able to do more testing but the seating depth I really think has helped compared to other hand loads I've worked with in the past.

Thanks,
Rob

[fgw_in_fla]

The pic of 42.2 you posted....

When I see that I go .2 up & .2 down to find the sweet spot. You'll find out pretty quick which way it is. Put 3 of 4 rounds together in those powder weights & make 2 sets. You should be able to see what you need to do next.... 42.2 might just be the magic spot you're looking for.

Once you're happy with the charge weight, you can modify your COL or go on to the next stage of obsessive / compulsive disorder.....

Good luck.

Frank in Fla

[supergolfer18]

handsomerob: I saw it was IMR 4895 that's why I asked if you saw pressure at 43gr since that is where you stopped and Hodgdon listed 45.4 as max. Might want to work up to see if have a accuracy node higher around 43.5ish according to Dan's OCW and reading other's OCW range

[handsomerob]

handsomerob: I saw it was IMR 4895 that's why I asked if you saw pressure at 43gr since that is where you stopped and Hodgdon listed 45.4 as max. Might want to work up to see if have a accuracy node higher around 43.5ish according to Dan's OCW and reading other's OCW range

Okay, no I did not see pressure signs at 43grains. I just haven't had time to get to the range to do the other half.

[acemisser]

i buy several boxs of factory and shoot them over the chrony..usually only 5 shots..
once I got the MV's I then set out to reload if there is one that is a decent load for what I want..

And I save the factory ammo incase I need it later for hunting or home defence or whatever...