AR / 223 55gr Load Data Extreme Variations in Starting Loads Help

[CowboyinIL]

I started to reload 55gr Hornady Z-max bullets yesterday with Hodgdon H335 powder. I went to look up my starting loads in 3 different loading manuals and had 3 really extreme (in my humble opinion) starting load variations from each reloading manual.

Hornady 8th Edition - 21.4
Lees Reloading Manual - 23.0
Lymans 49th Edition - 24.0


I'm thinking I should start with the Hornady Load because it is a Hornady bullet, and I'm thinking that the Z-max is really the V-max bullet rebranded, but that seems really low and I'm not sure that will cycle my M&P AR-15 16" barrel.

Also, the Max Load in the Hornady manual shows a max load is 24.2 grains of powder, which is very close to Lymans 49th starting load of 24.0.

Any thoughts as to what would be a good starting load?

[mohr308]

I would start with the lower grain (21.4), that powder has a faster burn than what i am currently testing with the v-max 60gr. thats just my gut feeling

[Wahoo95]

My plinking load is 25gr H335 or WC844 under 55gr Hornady 55gr FMJBT and it not a max load based on my data. Different sources different data.....that's why we should always work our loads up.

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[steve4102]

Hodgdon data for 55gr bullet, 23gr to 25.3gr.
Speer #13 24gr to 26gr.
Sierra #5 23.6gr to 25.7gr for AR type rifles.
23gr to 27.5gr for bolt action rifles
Nosler #6 23gr to 25gr.
As you can see most data hovers around 23gr for a starting load. IMO Hornady data is watered down compared to most other sources. When I have one source(Hornady) that is way low compared to several other sources I through it out, I also through out the one that is way high.

[DeadCenter]

I just picked up a box of 55gr Z-max and started playing with some loads of 25 +/- .3 gr H335. 25.3 gr of H335 with the 55gr Dogtowns are very accurate out of my 1-12 20" .223, but not so much with the Z-max. I will try a few more with the 335 and also try some H4895 and Varget and see how they work.

[dcobler]

I would say load up ten of each (as long as your not over max anywhere) and test them all to see what works best for you.

[CowboyinIL]

Thanks guys for all your insight. I started the loads at 22.5gr of H335 and worked up 3 rounds of each to 24 with .5 grain increments. This seems to be a safe starting point as you've said / shown in your manuals and mine also that most starting data begins at 23gr. I have yet to get to the range to test them though.

I did notice that Hornady does have you seat the bullet approx lower than (.03) than the Lymans 49th edition which would in essence give the bullet more pressure. So that is probably why they have lower powder charge loads.

Let me know what how your loads work out with the Z-max H355 if you get a chance and try different loads.

Thanks again guys.

[NESHOOTER]

At this point in your reloading a chrony is indespensible and then you can clock your FPS and have repeatabilty with your scope settings and reticles as many scope co's have programs to use FPS on your rounds.

[Marco Califo]

And had some primers pierce.

OTOH, I also just laddered surplus 844, which uses H335 data, from 23.5 to 28.5 in 1.0 gr increments, and accuracy got better each step. 28.5 is the specified load in:
TM-43-0001-27

Non-of the loads were compressed, and 28.5 looked like 98% of case capacity. That may be why it was the most accurate.

The primers were CCI SRP #400, and M193 projectiles.

This spread in loads over 6 charge weights was selected for exactly the reason as you asked: the published loads were all over. But, if I went this high with H335 I think I would have had pressure problems somewhere around 26 grns. The only way to know is start low, follow a reasonable method working up, and examine the spent brass.

[steve4102]

I did notice that Hornady does have you seat the bullet approx lower than (.03) than the Lymans 49th edition which would in essence give the bullet more pressure. So that is probably why they have lower powder charge loads.

Actually just the opposite is true. The shorter the OAL the less the pressure. This was posted by our Moderator UncleNick, I hope he doesn't mind me posting it again.

[Marco Califo]

I did notice that Hornady does have you seat the bullet approx lower than (.03) than the Lymans 49th edition which would in essence give the bullet more pressure. So that is probably why they have lower powder charge loads."
Actually just the opposite is true. The shorter the OAL the less the pressure. This was posted by our Moderator UncleNick, I hope he doesn't mind me posting it again.

Wait a minute here. You are making an assumption that shorter COAL will, in all cases, cause a drop in pressure. That is a fatally flawed assumption to put your name on. That is not what UncleNick's chart says at all. Nick's chart is clearly labeled "Distance off the lands".
It is generally true that seating more deeply does typically raise pressures.
It may be true that seating further from the Lands (thus deeper) may decrease pressure in certain rifles with certain loads. But to say that seating deeper lowers pressure, without extensively qualifying in what specific instance this may be true, providing data to support it is just not right.
It is a Red Herring; it does NOT prove all Herring are Red.

That same chart also shows pressure increasing with on BOTH sides of the dip. So, close to the lands, AND, pushed further into the case, Both cause pressure increases.

[steve4102]

It also shows the increase in pressure starting at 250 thousands off the lands. You ever load that short?