Reduced loads of slow powders and SEE with cast!

[andym79]

Hi guys, whats the likelihood of experiencing a SEE when using a reduced load of a slow powder and a cast bullet!

It seems from what I have read CB will not get stuck and result in a pressure spike! I am however still uneasy about loading up with a slow power in reduced loads!

Also can a reduced load of H4831 really produce the same velocity in a CB with 12 grains less than it takes to get a jacketed one there?

There really insn't much published data at all for slow powders and CBs!

[GhostHawk]

First off I'd be carefull if you use IMR 4350. I have a couple pounds of it, I think mostly because it is not popular. Full case loads or use another powder is what i've been hearing. I did have some luck using the 4350 with a 40 gr charge with just a tiny piece of poly filler to fill the empty space. Not shoved, tamped, or wadded at all. Just a little piece fluffed up and inserted then seat the bullet above it.

I've had very good luck using IMR 4895 in Mosin 7.62x54r, and 7.62x39 reducing down to 20 grains with no issues, drastically reduced recoil, slightly lowered point of impact at 50. But good punch, fair accuracy, and much more pleasant to shoot.

I'm using mostly a .312185 2r gas check design by lee and I've been very happy with it. I also have the .312155 and it is ok, but my guns seem to like the 185's better.

The IMR 4895 is so much easier to work with, so much more flexible that I've just run with it.

[andym79]

I should outline what I mean by reduced load. The max load for H4350 and H4831 are 44 and 47 respectively! I am looking at loads of 30-33 and 35-38 respectively in the 6.5X55.

[GrizzLeeBear]

SEE events are unpredictable by nature and difficult to repeatably reproduce. They do not necessarily come from a bullet getting stuck in the barrel, which is more correctly a "squib". The one thing that all the research I have read on the subject agrees on is that low case fill with slow powders (like 80% fill or less) produces very unpredictable burning characteristics. In one case a reduced load of slow powder will produce very poor burning and you get a "squib" leaving the bullet stuck in the barrel and becoming an obstruction for the next shot. Another theory is that you can get a "flashover" where the primer flame jumps across the powder (since it is laying in the bottom half of the horizontal case) and the powder burns from both ends simultaneously making it act like a very fast powder. Say, like loading a 30-06 with a half a case of Bullseye, KaBoom!

In any case, trying to use reduced loads with slow powder is EXTREMELY RISKY! You need to fill the case or work with fillers to keep the powder against the primer and take up air space. Otherwise you are much better off sticking with the medium-fast powders that are proven for the caliber you are loading.

Also, 4350 is notorious for producing SEE events with reduced charges.

[tomme boy]

In a jacketed load. The main rifle you have to worry about is a Swedish 6.5mm. Cast, not so much. Wait for Larry on this. I know he has done a bunch of pressure trace loads.

[Ben]

andym79

Quote :

" I am however still uneasy about loading up with a slow power in reduced loads! "


---------------------------

I'm more than " uneasy ", I'm simply not going to do it !
There are too many other safe powders like IMR - 4895 that tolerate reduction in charges. Hodgdon even offers reloading data for reduced charges for IMR-4895.

http://www.imrpowder.com/PDF/Youth%20Loads.pdf

[btroj]

Yeah, I'm listening to Ben.
Ask yourself this- do YOU know more than the experts at the powder company?

I'm not putting my firearms, or myself, in danger because I "just gotta know".

[leadman]

Just so everyone knows, the Hodgdon reduction to 60% of a max listed load in Hodgdon's data is ONLY for H4895, not IMR. I spoke with the ballistics tech at Hodgdon after Dave Scovill seemed to want to ignore this fact in a couple recent issues of Handloader.

I reduce my loads due to a bum neck so do not use slow powders as the extra powder adds to the ejecta and hence recoil.
I have used WC872 in the 6.5X55 with 140gr jacketed bullets and had very good accuracy with only slightly reduced velocities.
The older Accurate manual has loads for their 870 for several cartridges. I use it in my 7mm Rem magnum as does my son. Hardly reduced though at 80 grs.
There are many threads on this and I think one is going right now.

[Yodogsandman]

I tried a load of 34.0gr of Reloader 19 with .5gr Dacron this weekend in my 6.5x55, M38, 22" custom. This was using a 160gr Lyman 266645 boolit "dressed", all lubed up with gas check on. It was too fast! Just too fast for my alloy. One foot or so group at 50 yards. I did have one lucky group that was 6 inches for 5 shots. I had no signs of any excess pressure. I dropped the load down to 31.0gr Realoder 19 with .5gr dacron added and will try them out again the next trip.

Some time ago I cut the dacron sheet into 1/2" squares and they weigh .5gr or so. I pull one out of a coffee can and pull the fibers apart, folding them back into/onto itself until I have a nice fluff ball. I then push it into the case mouth (in this case) with a wooden match stick ( with head removed) so that its just in the case to the powder but, not compressed at all and still fluffy. The fluff filled the case from the top of the powder charge to the base of the boolit. It's time consuming but , not hard at all.

You should be careful with anything you load. You should certainly read the sticky on using fillers. I use dacron fluff as a safety measure to prevent SEE when using reduced loads of slower burning powders. Using a little fluff of dacron filler to keep the powder charge positioned to the rear of the case is just another tool for us to use. It's not that much different than raising the barrel to position the powder rearward and slowly lowering the barrel to shoot. Just a better way of doing it. I've done it for about 20 years, mostly in my FR8, 308 win. (7.62x51) when using surplus powders. Notably, one powder that was close to Accurate Arms 2230. Using dacron tightened my groups and kept the cases from being covered with soot with each shot. I've shot many thousands of boolits with it. Enough to use up a few 8 lb jugs of powder.

[rhead]

The situation is too easy to avoid to take the chance. go to a faster powder if you need a slower velocity.

[andym79]

The situation is too easy to avoid to take the chance. go to a faster powder if you need a slower velocity.

The thing is I do not need or want a slower velocity, I am chasing high velocity in the Swedish Mauser M96 6.5x55! I want an accurate load to a minumum of 2100fps if possible. The load data for cast bullets is limited.

For a 140 grain jacketed projectile the data suggests 39.5-44 grains of H4350 and 42.5-47 grains of H4831.

In order to achieve similar performance with cast bullets Quickload suggests 32-37 and 36-39 grains of each powder respectively. I have seen reference to loads used of both powders lower than those Quickload ranges.

[44man]

The Swede is a big problem with the long leade. Too much room for boolit movement and most times the primer pressure will push out a boolit before ignition, powder then can burn towards the case head.
My friend and I used the same load of 4831, If I remember it was 46 gr with the Hornady 129 gr. Super accurate but we both had SEE events. Neither rifle was damaged but we needed a mallet to open the bolts. Never found the primers. At least the gun is strong.
I worked loads with Varget and 36 gr with a 140 gr bullet gave me a group of .436" at 100. With the 129 I use 37.5 gr. Make sure enough bullet/boolit is in the neck.
I would never download 4831, our SEE events were with good loads. Filler will not save you.
Cast can exit the case from primer pressure easier then jacketed, too much running room to rifling. If a boolit even stutters, pressure will skyrocket.

[andym79]

So small for bore projectiles and H4831 are a big no no!

Can a cast bullet really get stuck in the forcing cone long enough, I guess anything is possible!

[Outpost75]

One of the best references on this subject, from Finland: http://guns.connect.fi/gow/arcane1.html

[44man]

So small for bore projectiles and H4831 are a big no no!

Can a cast bullet really get stuck in the forcing cone long enough, I guess anything is possible!

You need resistance to bullet/boolit movement is all. Against rifling or case tension.
Guys use "M" expanders in revolvers don't know that the gap is saving their guns. easy to pop a boolit into the cone and rifling with a primer before ignition. Some primers have 2000# of force. They talk of air space with H110/296 but then blow out a boolit to increase air space.
I had boolits stick in bores of the .454 without any powder burn by using starting loads of 296. SR primer is just wrong for the case. Lot of pressure with not enough fire for the airspace. The case is large and needs a LP mag primer but the .44 is too small for them. Accuracy goes to pot from different boolit movement from a too high pressure primer. Imagine the powder actually going off with the boolit up the bore. Gas exits the gap to save you and the gun.
Not so in a rifle, move the boolit out and get ignition can be a disaster. It is not bore size and 4831 is safe in small bores with the right load.
The swede is like a revolver without the gap release. A boolit out of brass, in the rifling is just like reducing the charge, air space. Powder is pushed with the boolit and then ignites, pressure is reversed.
The boolit plugs the bore.
If guys knew how many revolver loads are SEE events, saved by the gap, they would think twice.
How do you think I get accuracy? I reduce boolit movement at ignition. NOT with crimp, stupid idea.

[Larry Gibson]

1^stof all lets get one thing clear; SEE is caused by a bore obstruction, most often the bullet itself becomes the bore obstruction because it gets stuck in a fouled or eroded throat (or both) and the burning powder builds the psi to a very higher degree before the bullet moves. This most often occurs with jacketed bullets either light for caliber or with long bearing surfaces and reduced loads of slow burning powders. An SEE can also be caused if the bullet is heavy enough that the powder used generates excessive psi before the bullet moves very far. This is most often prevalent with heavier cast bullets for caliber and using some of the slower fast burning powders and the faster medium burning powders.

So how do we know this? The cause of an SEE is now well documented and has been reproduced in labs with pressure measuring equipment and in the field with, if lucky, nothing more than a bolt that needs to be hammered open…..if not lucky then with a destroyed rifle/handgun and hopefully limited injuries. With my ownpressure measuring equipment (Oehler M43) I also have reproduced such events, but knowing what they are and the indicated symptoms, stopped short of the actual event. I have however had to pound open a couple bolts during my learning curve of what the indicators meant. The SEE caused by the know bore obstruction is well known and documented.

The theory of “detonation” of small amounts of fast burning powder in a large volume case is also misunderstood and proven inaccurate. Besides such small amounts of powder nothaving the physical potential to cause the catastrophic event even if they did “detonate”having been proven such has never been reproduced in any test. Detonation of reduced loads of slow burning powders also has not been proven in any test. Both remain unproven theories and have been repeated so often over the last 50 or so years they have become “fact”. Until proven in reproducible testing they remain non facts or myths.

An SEE event should not be confused with an overloaded cartridge or with a defective cartridge case or out of battery firing. While the end results may indeed be the same the actual cause is different. Understanding the root cause of all these catastrophic events helps us prevent them. Ignorance of the actual cause of such an event can lead us down another just as hazardous path to another different such catastrophic event.

In my testing, including pressure testing, of slow burning powders in the 6.5Swede (documented in the thread) powders such as 4350, H4831SC, RL22 and AA3100 were used at less than 50% load density with a filler. There was absolutely no indication of pressures piking and no indicators of an impending SEE were noted. Those powders ignited and burned progressively just as they should have.Understand that when a filler is used correctly, dacron or buffer type, the dace capacity is reduced by the filler. Hence, with a given load with and w/o a filler, the load with the filler will give a higher psi.

AsI have suggested to andym79; when going to a slower powder (such as he is doing going to Varget after 4895) use the max accuracy load of the faster powder as your start load of the slower burning powder. If a filler was used (dacron or buffer) continue to use that filler until load density is over 80 – 85%.

LarryGibson

[44man]

Larry, Varget is faster then 4831. In the area of 4064. Easier to ignite too. 4895 would be a good choice too.
Varget can be used in small cases like the 7BR and 7R, 7 Waters, etc, even though Hodgdon says it is too slow.
You are correct in that an SEE event is a bore obstruction "stuck bullet". A filler will not prevent it if conditions are right. Filler keeps powder closer to primer flame, true but a moved and stuck boolit is still a bore obstruction.

[44man]

What guys do not understand is we shot thousands and thousands of shots with our loads before we got the SEE events. So I can't tell you the book loads listed as the most accurate are safe any longer. It was not the load, it was what the bullet did before ignition. I know very well what happened, we did not seat deep enough. In the Swede, seat to the cannelure. Get brass around the bullet. Lubed, cast can move easier. Retain the bullet first. Just like my revolvers.
just how far can an "M" expander be tossed?

[Larry Gibson]

44man

Understand quite well what burning rate Varget is. The choice was andym79s next move, not mine. If you read the threads I suggested the slower powders; 4350, RL19, H4831SC and RL22 as his next move. He chose to go with Varget.

What guys do not understand is we shot thousands and thousands of shots with our loads before we got the SEE events.

Also understand that quite well which is why I said; the bullet itself becomes the bore obstruction because it gets stuck in a fouled or eroded throat (or both) and the burning powder builds the psi to a very higher degree before the bullet moves."

Your use of "thousands and thousands of shots" obviously led to the "eroded" throat and that combined with fouling induced the SEE. In other words all your shooting ended up creating the conditions necessary for the SEE to occur.

Larry Gibson

[Hamish]

Your use of "thousands and thousands of shots" obviously led to the "eroded" throat and that combined with fouling induced the SEE.
Larry Gibson[/FONT]

Im having trouble figuring out how you "obviously" know that his throat was eroded. I would think that you would have to physically examine and measure it.