Finding The Sweet Spot - .223Rem Loading

[stavman11]

One of the funnest things to do is FIND that sweet spot...

Find a nice starting spot with powder and an ACCURATE bullet
Ladder some charges... I do 10-15 of each.. shoot 5... and do it 2-3x in a range day
Chrono/Log them all
Find the best Options... Ladder some more... Rinse and Repeat

Once you find yer sweet spot or spots.. Play with COL and see if it effects the Sweet Spot much... and adjust accordingly

As far as Velocity recording for the Final SWEET SPOT... Not all factors involved
Primer, COL, Powder, Bullet, Barometer, Sun Location, Moon Location, Wind, etc etc etc

But seriously.... Catalogue everything... I just look at what Powder Drop I need for a specific Bullet... set it Up.. Check the COL... and load away

Have fun... dont overthink it too Much.. Unless you can shoot at 1MOE at 300yds+ it really wont matter


Stav

 

[armoredman]

Just stared loading .223/5.56mm again with a new gun, and none of the old perfect recipes are perfect now. The fun of reloading is getting to that sweet spot, if ever.

 

[BBarn]

Loadmaster, I understood your question from the get go. I don’t know the answer, but I find the question/suggestion interesting. It does seem that for a particular firearm, bullet choice and velocity would be major factors in the sweet spot, and that powder choice might have a somewhat lesser influence.

As is obvious from the comments here, those on a quest for sweet spots don’t typically approach it in the manner you are asking about. But it would be interesting to try out your suggestion. Take a gun, find a bullet it shoots well, and tweak the powder charge until accuracy is optimum and note the velocity. Then switch to a different powder of similar burn rate and adjust the charge until the same velocity is reached (without paying much attention to accuracy).

Then start the accuracy testing with the “similar” powder. Shoot for accuracy at that velocity and then adjust the powder charge up and down to see if accuracy is optimum with the “similar” powder at the same velocity as the original powder. If not, you can see how much different the sweet spot (and velocity) is with the “similar” powder.

 

[SARuger]

I use a heavier pill than talked about in this thread, 75g AMAX.

I have run ladder tests on the following powders;

Varget
Reloader 15
BLC-2

The RL-15 has given me the best groups so far with BLC-2 coming in a close 2nd. Varget gave me 3 MOA groups where the RL-15 gave me sub MOA groups.

All rifles are different! Mine is a 1-8 twist Ruger American

 

[Nature Boy]

I couldn't get the 75g AMAX to group with my 1:9 barrel but 69g SMKs do great. 10 shots each at 100 yards

 

[Load Master]

Loadmaster, I understood your question from the get go. I don’t know the answer, but I find the question/suggestion interesting. It does seem that for a particular firearm, bullet choice and velocity would be major factors in the sweet spot, and that powder choice might have a somewhat lesser influence.

Thanks BBarn. My theory, when ladder test are done, this is really a exercise in timing. The barrel of a rifle is a beam that has bend modes. Accuracy, the point of impact compared to point of aim, changes due in part to where the exit end of the barrel is pointed at the instant the bullet is exiting. This isn't something easily explained in a forum so people understand what I'm working on. This could be my lack to explain it clearly. I'll give a try however, if there is an interest.

 

[Hangingrock]

Load Master, its to bad that Precision Shooting Magazine is no longer published. I think you would have enjoyed the technical articles.

 

[Load Master]

Load Master, its to bad that Precision Shooting Magazine is no longer published. I think you would have enjoyed the technical articles.

Yep, you are correct. I've been told I'm a little excessive with my hobbies by the other half that lives with me.

 

[spitballer]

I've become a great believer in matching a pressure curve (directly related to propellant speed) to barrel length. Published load data is based on a 24 inch barrel and the propellants that show good results with the test barrel may not be optimal for a carbine. Conversely, propellants that perform well with the 24" test barrel may not be optimal for a longer barrel, and FWIW I've found that an exceptionally long barrel seems to perform better with a pressure curve that's been extended by combining propellants in layers with the slower powder burning first (not surprisingly, the military has done research in this area: https://ia600300.us.archive.org/5/items/velocitypressure00culv/velocitypressure00culv.pdf). Just be advised that you're on your own if you try this stuff yourself: NONE of the reloading manuals I've seen support this technique.

 

[armoredman]

Absolutely true - every single loading reference I have read has been very emphatic about never, ever, combining powders. Leave that to the manufacturers.

 

[Load Master]

Interesting read spitballer, not for me, at least at this point. Talk about making things more complex.

 

[spitballer]

Talk about making things more complex.

Yeah, that's one thing the Army doesn't like - complex. Especially on the battlefield where simpler is better. IMO duplexing is destined to stay on the fringes anyway: the military is unlikely to use it with small arms, law enforcement is unlikely to use it for insurance reasons, and with modern arms and propellants it's just not necessary, not like it may have been with Kentucky-Style long guns using black powder. Possible exceptions might be target rifles using exceptionally long barrels with tiny cartridges. But an AR with hard FMJs? Forget about it.

 

[outlawjw]

I have tried exactly what you are talking about . I had some reloads my son in law gave me with a gun .I knew what bullet , primer , coal ,& velocity he was loaded to so I proceeded to find his charge & powder through the use of matching his velocity . I got 3 powders to produce the correct velocity but none of the three matched the accuracy of his reloads. Finally I called him ,got the right powder & wah lah at the same velocity it shot the same accuracy as his reloads did . I am like you & figured what powder didn't matter as long as velocity & everything else was the same ,but no the time it takes for each powder to reach a given velocity is different & thereby changes the harmonics.