Home Forums Reloading Varmint Rifles Max load question

I started working up a load for my 223 ackley this past weekend. I got 4 different sources for my min max using a 62 gr barnes ttsx and cfe223. Hodgdons website was the highest at 27 gr which shows a velocity of 3,200 fps. I understand that these numbers are with a 24" 1:12 twist and I am running a 22" 1:8 twist so my numbers will be slightly less. However, at hodgdons max load recommendation I am barely getting 3,000 fps. There were no signs of pressure so I ran some more bullets up by .1 gr each until I hit 28 gr. Although I saw no effects of over pressure I still felt as though I should probably stop becouse I just don't like to push things when it comes to safety. But, even at 28 gr I am only getting 3,108 fps, almost 100 below what hodgdon shows at a grain less. So, what is more important in terms of safety, my chrono numbers or pressure signs in my brass? I am not a speed freak, more of an accuracy freak actually but, when using the barnes bullets I like to get max speed out of them as this produces better bullet performance on the all coppers.

If I'm reading it right you're using Hodgdons regular 223 data in an AI chamber. You will get less pressure and velocity that way.

Yes that is correct. I can't find anything for this bullet and powder combination in an AI in any manual.

You should be on the safe side then.

Hopefully some AI shooters will chime in.

I've done a lot of experimenting with loads for the .223AI albeit not with Barnes 62TTSX...Ive been shooting the 55 TTSX and earlier, the 50 TTSX

Best velocities, and accuracy were obtained using TAC and H335....3500 fps and 3473 fps out of a 1 in 8 22 inch barrel.

H335 however is extremely temp sensitive, for me to the point that it is unusable.


TAC does not suffer from that malady and I wouldn't hesitate to try it with 62 grain Barnes.

Max load with a 55 grain TTSX is 28.5 grains for both TAC and H335


My second go to powder is IMR 4895...28 grains of it...but it only brings about 3300 FPS... and Im with you on the faster I can get a Barnes to go...

Well I have no issue trying TAC other than I already own 5 pounds of cfe223.

H335 is absolutely not "extremely temp sensitive" in the 223. Nor is TAC magical, Nor are "insensitive" powders a universal thing.
Denton has shown this a few different times. Some of the testing is up on RSI's website.

Don't "read" Pressure signs in brass. Watch the chronograph. Very carefully calibrated copper crushers are known to report swings on the order of 15-20,000 psi, for the Same reference load when used over @ 45,000 psi. Unknown brass alloy with unknown primer cup alloys being stared at by the average Joe, aren't magically more accurate at it. From Pressure Tracing a few different production rifles, generally, Pressure "signs" in modern rifles manifests itself a bit north of 75,000 psi.

From PT work with the Creedmoor and a few powders, in the operational Pressure listed (min to max loads) each additional 75-100 fps will come at the cost of around 10-15,000 psi. Hodgdon warns on all their bottles of powder a 10% lot variation.
Does the data give tested lots? No, so don't think you have the same thing.

Pressure tested data happens in SAAMI min spec equipment, you have loser tolerances in a production rifle; so more gas bleed-off. When you match/pass book velocity, regardless of powder charge, you have gone over-pressure.

I don't think so. Forget the chronograph. It's only an indirect measure of pressure and a bit crude at that. There was a gun purveyor who had 10 "identical" rifles in which he shot the same load. Velocities between the rifles varied by as much as 200 fps.

Pressure signs are going to vary depending on the cartridge and the gun. With a 223 cartridge, there probably isn't going to be much primer flattening or even sticky extraction in a bolt gun. What will probably happen first is a primer leak or a pierced primer.

What I've found useful, if you're shooting an accurate gun that is, is to look at group size. As you start low and work up, groups will generally get smaller up to a point and will then start to open up again; sometimes with a marked POI shift. I stop where the groups are the smallest.

This is not necessarily so. I have a standard 223 that exceeds Hodgdons book max speed at under max charge. It also exceeds Noslers max speed for a given charge under max and have had no problems at all.




Again the highlighted is not completely true.

Shoot your groups for accuracy over a chrono.

I have had stiff bolt lift, hard extraction, and no primer leak or pierced primers from a max load of 335 and 8208 when the load was developed in cooler weather and then shot on a much warmer day. I have found 335 to be very undependable @ max load above 90 degrees. Plus its extremely dirty.

OP the 223 Ackley should give a case capacity gain of 2.2 to 2.8 grains H2O over the standard 223.
So I would work up and watch the chrono and group size, groups may get smaller but could get larger. Its also possible that you have reached a plateau where adding more powder will not gain you any significant increase in velocity. As others have said you may have to go to a different powder/primer combo to get what you are seeking.

Use the chronograph. It is seems to slow, it is. Add more.

If it seems to fast, it is. Back off.




Travis

Nope, TAC aint magical, but its damn good for a lot of applications. H335 has proven, and quickly to be temp sensitive in the four rifles ( 2 plain vanilla 223s and 2 .223AIs...) that I have tried it in. Middle of the road loads...I can guarantee a blown primer in the first 7 shots...due to the gun warming up. On a 90 degree day I can virtually guarantee a blown primer on the first shot....and this in rifles you plan on putting100s of rounds through on a given day on PDs...

As they say Your Mileage May Vary, but in my rifles, where I live and how I shoot, it is unusable.


That said, lots of guys here use H335 religiously and experience no problems. Guess Im just the lucky one...


I have heard good things about cfe223...

I've also experience extreme temperature sensitivity with H335 in the 22-250.

My experience with actually chronographing H335 and TAC loads in various temperatures, outdoors with the amma AND rifle at ambient temperature (as opposed to running them through a rifle attached to a Pressure Trace) is that H335 is indeed far more temperature sensitive, both to cold and heat. And I have had some of the same problems as Ingwe when using H335 on hot days when prairie dog shooting.

One factor with with the .223 AI (and in fact probably the major factor in velocity gains over the standard .223) is the SAAMI maximum average pressure for the .223 is only 55,000 PSI, which is reflected in published data. Normally traditional "pressure signs" don't show up until somewhere over 65,000 PSI, so handloaders working up loads in their .223 AI's are often loading to at least 10,000 PSI higher pressure.

Thanks for confirming gentlemen. I guess I'm not the only lucky one!

But i keep seeing other members use H335 and many even on PDs and such, with good luck. All I can think of is their idea of high volume shooting and mine are totally different concepts.


FWIW JB I have no way to pressure test so I worked up my AI loads slowly and carefully..H335 is the only one that ever showed excess by blowing primers. My max load of TAC or IMR4895 has never given me a bobble...at any temp.

Same here. I worked up a load with H335 for the 22-250 in the winter and was blowing primer shooting Pdogs on a hot summer day.

In the AR I've had H335 loads that were fine in the summer fall fail to function on cold winter days. My experience seems to mirror Johns that H335 is sensitive to both heat and cold.

I haven't shot H335 in the cold, but I worked up my AI load ( 28.5 grains H335 and a Barnes 55 TTSX) in Montana at about 50 degrees...took it to Texas, checked zero at 90 degrees and blew the first and only primer I tried...put the gun up and used a spare...

That aint my AI load now....

Tom,

It might also be that some H335 users stick to milder loads.

In fact I know one who has never chronographed his prairie dog load, or even shot groups with it. Instead he sights his rifle in on PD's in the field. Works for him, but since he's never seen any "pressure signs" on a hot July day on a dog town, I suspect he's using a couple grains under max listed charges.

JB in two plain vanilla 223s we loaded a mild 24 grains of H335. Four shots later, in a warm chamber.....poof! Both guns. ( 50 grain bullets)

I don't know how those other folks do it.....

So a chronograph is an indirect crude way of measuring pressure... But the average joe staring at a piece of unknown brass isn't??!!
Where do we get velocity out of the bullet from, if it isn't the pressure behind it?
The fact that various rifles show different velocities is due to the varying manufacturing tollerances I spoke of, in production rifles.

When you are only matching charges and your velocity exceeds book values, it's because you are using the same thing as the book. It is possible that you have some tight tollerances, but not likely. The reasonable explaination is the different lots of powder(tested, Vs. what you use), when you burning speed is faster, you have higher pressures.

Denton has shown rather clearly that the "powder" isn't quite the devil you think it is, when it comes to temp stability. Here is one of his articles.

https://www.shootingsoftware.com/ftp/Pressure%20Factors.pdf

And a few other articles you may find interesting.
http://www.dtic.mil/ndia/2007smallarms/5_8_07/Webb1.pdf

Read what they say about "universality"
http://www.accuratepowder.com/faq/

Yeah, I feel your pain, having been there before.

Have never had that happen with TAC, and I've gone through several 8-pounders not just in .223's but the .204 Ruger and .17 Fireball.

Also tested TAC at 70 and then at zero and in the 90's over a chronograph. Per usual in my tests, EVERYTHING (not just the ammo) was cold or warm, just as it would be when hunting. Am not going to look it up right now, but the TAC loads was around 26 grains with the 50 Ballistic Tip, and got just under 3300 fps from an Oregon Kimber I had back then.

At zero it averaged EXACTLY the same velocity as it did at 70, which was obviously due somewhat to chance, as even when chronographing several strings of the same load, on the same afternoon, they won't be exactly the same. But it did impress me some.

At 90+ the load was in the low 3300's, but have seen many other powders gain a lot more velocity in warmer weather. In fact have never chronographed any load, with any powder, that didn't gain some velocity at much over 70 degrees, even the Hodgdon Extremes, but with so-called temperature-resistant powder the rise in velocity is less than with what might be called conventional powders.

Have also "greenhoused" a few rounds in a Ziplock bag, along with a small thermometer, when doing warm-weather tests, to get the ammo temp up to 120 or so. Then have shot them in a "cold" barrel and also one that had been warmed up with a number of rounds. That can get interesting!