Anyone ever load below minimum?

[shooter444]

Has anyone ever loaded below minimum charge publications?

I am about to work up some light for caliber bullets, for a new rifle in an old caliber to minimize recoil as much as possible. I calculated the foot pounds of energy at just over a 2,500FPE @ 3,000 feet per second. That is the minimum powder charge data, published for this caliber / bullet / powder.

Since this is no where near a slow load, like trying to work up a subsonic load, with the caution over squibs... I am assuming I can drop down to a velocity of 2,600FPS that would result in a little over 2,000 Foot Pounds of Energy, without any such worry over squibs. And then fine tune for accuracy.

I have always loaded and chrony'ed with the goal of acquiring the fastest, most accurate load,... never went the other way,... trying to slow down below published minimum charge. So, I am wondering if there may be some issues/cautions I should address,... or, not.

I assume all will be well,... but, I also know,... assumptions are the cobble stones, that pave the road to hell !

Thanks!

[Flash]

Yeah, I do it with virtually all my handgun calibers, eight total. Rifle is a different matter. You're using slower powders and there's this thing called detonation that nobody has figured out yet other than it happens in rifle cartridges using reduced loads of slow burning powder. Secondary Explosive Effect is more properly what is probably happening.

What you can safely do is find loads using faster burning powders like handgun powders and shotgun powders that will give you the results you want safely.

https://www.nrafamily.org/articles/2018 ... henomenon/

Recently, we've discussed hangfires, misfires and squib loads and how they might affect you as a shooter. However, in our first discussion we told you that there were four types of ammunition malfunctions that you should know about—and so far, we've only covered three. The fourth is called "detonation phenomenon," and it's the most elusive one to quantify. Here's what we know (and what we don't), as well as what you should know.

For years, shooters have reported unpredictable pressure excursions capable of damaging or destroying a gun when light charges of very slow powders were used in large-capacity cases. This detonation phenomenon has thus far proven difficult to replicate under laboratory conditions. Nonetheless, many ballisticians regard the phenomenon to be real and have developed a variety of theories to explain it.

One such theory postulates that a small powder charge in a mostly empty case can produce reinforcing shock waves inside the case. Another theory claims that the ignition of a small charge of very loosely packed powder granules can result in more or less simultaneous, rapid burning of the charge, producing excessive pressure.

Whatever its cause—or, in fact, whether or not it occurs—detonation should not be ignored by the cautious shooter and reloader. Loads less than the minimum loads listed in published data should be avoided, as should any ballistic "experimenting" with slow powders for which reduced load data is not available.

[shooter444]

Good info Flash, thanks. The powder isn't slow by any means, but, I wouldn't classify it as FAST, either.

I decided to look over the load data I have, again, and realized that the minimum suggested load is LESS than a 10% reduction off of the maximum,... max=55.3 grn,... min =51.7 grn,... published load data, which would be a far cry from a lightly filed case. This is my first time using this powder.

IMR 4166,... max=55.3 grn,... min =51.7 grn published load data.

As I stated above, I am only thinking about a 400 FPS reduction taking the original minimum 3,000fps, down to 2,600fps, but, it is still unknown territory for me.

After reading your post, I am definitely leaning towards forgetting the whole idea.

[Flash]

What's the caliber and bullet weight? I'll see if I can come up with something.

[shooter444]

It's for a new 30-06 sprg bolt gun I picked up awhile ago. I researched and decided to try IMR's 4166 new generation (not new anymore) ENDURON edition powders that are suppose to be great for temp resistance and cut down on copper fouling, only picked up a pound for initial load work up.

http://bulletin.accurateshooter.com/201 ... d-to-know/

I just got in a couple hundred 30 cal 130 grain Barnes TTSX bullets. I chose Barne's lightest 30 cal, that has multiple fouling rings cut into the bullet, so I can experiment with using my home brewed lube. I broke a rib fighting with a bale of hay while feeding horses and messed up my right shoulder a bit,... so, I am going for an effective hunting load with less recoil.

scroll down for quick ad video
https://www.barnesbullets.com/bullets/ttsx/

I shoot a lot of Barnes copper bullets in my 24" bull barrel AR, mostly 36 grain Varmint Grenades @ a tad over 4,000 FPS, lately. I load up their 60 grain BT's @ subsonic for my pump action,... real nice for varmint yard work.

thanks!

[Flash]

Okay, and I'm not sure how to read your original post. Are you looking for 2,500 fps or less? If less, how much exactly.

[shooter444]

No,... best go read again,... that was 2,500 FPE (foot pounds energy) @ 3,000 feet per second,... minimum load / charge.

I was thinking of just dropping the velocity to 2,600 + feet per second down from 3,000 feet per second, which is minimum load / data,... which would put me at close to 2,000 foot pound of energy,.... still a good amount, for yotes at a fair distance.

[Harrier]

So are you set on using the IMR-4166 powder you mentioned or are you looking for any light recoil load? If the latter I would check out some of the load manuals from the 50's & 60's for reduced loads... IIRC 10gr of Unique pretty much works in all rifles I have tried as a light load with lead bullets. OTOH if your wanting to use 4166 I would first check various other load manuals as many times they differ in what they list as minimum, then I might cal the maker... i don't know if I would go much under the published load as some powders NEED a certain level of something to ignite properly.... FPS is a secondary byproduct.

[shooter444]

Just re-read the OP, a little confusing, for sure,.... so I fixed it a little.

Flash, I am not interested in finding a different powder, or a different load,... I was just wondering about loading what I have at less than minimum load data,... and wondered if there were any down sides to doing such.

[shooter444]

Yah, like I just posted, not looking to change anything. Not looking for a really light load, either, as I just wrote.

Agreed Unique could do a extra light load,... but, I would go with Trial Boss, if that was my concern.

I don't consider a load with 2,600 feet per second, and 2,000 foot pounds of energy, a really light load. I was just thinking if I went 400 feet per second below minimum which would decrease the foot pounds of energy by 500 foot pounds,...edit,... I might get a little less recoil to add to the less recoil from the light bullet.

edit,...Basically, I am just trying to cut some corners to get less recoil. Which is why I am going to try lubing this copper bullet, hoping to get less resistance going down the barrel, as well as less copper fouling.

edit,...edit,...I just double checked, the rifle weighs in at 11 pounds with the scope, bipod, strap on check rest with pouch for extra mag and ammo, and sling,... I could fill the synthetic butt with used primers for even more weight. I have a sack I have saved, and use, for that purpose,... I find it amazing, how much shot primers weigh.

I do want to reach out to around 200 yards and still knock a yote on its butt.

Thanks for you help!

[Pale Rider]

I'll give my take on this. I've been reloading for 50+ years and learned from the old timers including my dad. This "detonation" term used to be called "a flash burn" by the old timers. It's where their isn't enough powder in the case that the flash from the primer goes over the top of the powder causing the powder to not burn from the back to the front and basically 'detonate". I was always warned not to use slow powders in small amounts in rifles (especially ball powders, because they are more position sensitive), in reduced velocity loads. Some powders work great for reduced velocity loads mostly for lead bullets because they aren't as position sensitive (like 2400). Now as far as what you're doing, if you look at the load data for 4166; the starting load is 51.7 gr with the 130gr jacketed bullet. If you look at the starting load for say a 180 gr jacketed bullet, the starting load is 45.5 gr. Would it be dangerous to say use 45.5 gr with the 130 gr bullet? I seriously doubt it. When I've done this type of thing I always use something to measure down into the case to see how low the powder is in the case. If it's at a 3/4 level and up, the chance of a flash burn is remote at best. Another thing to do is look at the loads for lead bullets. I'm using 32gr of 4895 with a 170gr lead bullet in my 8mm mauser (the Lyman book shows starting loads at 31gr), but the starting load for a jacketed bullet is much higher. If there was a danger of "detonation" then 31 gr would be a bad idea. The main problem I've had from going below the published data is not getting enough pressure to seal the neck inside the chamber and getting the cases smoked up, that's a big sign that you're going too far. That's why if I decide to go under the published data I go a half grain at a time until I get the desired load.

[shooter444]

Understood,... but, being that the max charge is 55.3 grains of IMR4166 resulting in 3,213 feet per second with a minimum charge of 51.7 grains of IMR4166 having a velocity of 3,003 feet per second,... I don't believe dropping down to a charge that would result in a velocity of 2,600 feet per second, would be a charge so small, that would create the possibility of "detonation".

But this is what I believe,... not what I KNOW,... hence my OP.

Thanks for your input!

[Flash]

Why not use a different powder? Why does it have to be just this one?

[shooter444]

Hey Flash,... IMR4166 met my requirement for a temperature insensitive powder.
For example, I develop loads here in the desert that can have 50 degree temp swings, from morning to late afternoon, especially in summer. With that kind of a temp swing, I chose this powder, which is on the list for Barnes 130 grain, with velocities producing 2,500 foot pounds, plus, of energy. There aren't that many ENDURON powders. I especially like the added plus of a powder formula claiming less copper fouling,... at least, according to Hodgdon.

I have wanted to try Hodgdon "ENDURON" powders for quite awhile now, but just never had a load I thought they would fit,... until now. There are only 4 ENDURON type powders made, and this is the only one for this bullet, in this caliber, that I have found load data for.

[Pale Rider]

Understood,... but, being that the max charge is 55.3 grains of IMR4166 resulting in 3,213 feet per second with a minimum charge of 51.7 grains of IMR4166 having a velocity of 3,003 feet per second,... I don't believe dropping down to a charge that would result in a velocity of 2,600 feet per second, would be a charge so small, that would create the possibility of "detonation".

But this is what I believe,... not what I KNOW,... hence my OP.

Thanks for your input!

I think you're on the right track. That's why I mentioned the fact that if you go too low on the powder charge the neck might not seal properly in the chamber and you'll get blow back on to the shoulder and smoke up the case. The minimum on the charge recommended from the powder companies is probably more to do with that, because particles can blow back into your face also. That's also why, if you want to try going below minimum to reduce the pressure and kick on your shoulder; you'd want to decrease a little at a time and watch for signs that would tell you that you don't want to go any lower.