I know slow powders need to concern about flashover and loaded to high fill rate or use filler when loaded low. Hodgdon has 7.62x39 load data for Banes 108gr RRLP with IMR 4227 and it shows starting load only 15.0 gr and max 17.6 gr. 15 gr is only a bit over 50% fill and 4227 is a medium burn rate powder. I load 123 gr cast bullet with 16 gr 4227 based on the data but I have to wonder if I should use filler to be safe! So how low a burn rate needs to worry about flashover! It is Hodgdon data, it must be safe! Banes load data shows 18.6 - 20.6 gr 4227 for the bullet.
What burn rate needs to concern flashover?
- Thread starter HankC
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Is "flashover" even a thing?
Anyway, you'll be fine with that as long as it has enough pressure to burn well. If it doesn't it will be sooty and likely inaccurate.
Anyway, you'll be fine with that as long as it has enough pressure to burn well. If it doesn't it will be sooty and likely inaccurate.
There you go.
In black powder revolvers, it's more cylinders firing than the one lined up with the barrel.
guess that's not what we're talking about
That is why I try 4227. I loaded the 123 gr Lucky 13 polymer coated cast bullet with H4895 reduced load but had unburned powder till 25 gr (29 gr is max). Even 25 gr I still see some unburned and 25 gr is pushing the polymer coating and smokes. I can put 8.8 gr Trail Boss in 7.62x39 but it shows vertical string at 50 yds which tells me I need more powder to be more consistent at that range. 4227 should give me the speed around 1500-1700 fps! It is a bolt gun.
someguy2800
Member
Look at accurate 5744. It is designed to work specifically for reduced loads. Acurates's load data shows 17.0-19.5 which gives 1730-1950 fps for a 123 gr plaited bullet. It will burn much better than 4895.
someguy2800
Member
H110 with a magnum primer would also burn clean. I load that in my father in laws 30 herrett which is nearly the same size case. 30 herrett load data is low pressure and should be safe to use.
FROGO207
Member
If you are worried about this (some call it detonation) try shooting after tilting the rifle back to put the propellant against the primer and crono it. Then try it with the propellant forward and crono it. Do you find a difference in VEL? With a 1/2 full case it should not be a problem. Any problems happen when you have 2-3 grains of fast propellant in a big rifle case. Then you need to stuff something in there to keep the minuscule amount of propellant near the primer hole to get consistent ignition. I have never seen detonation myself and while it may be possible I think that a double or triple charge of a fast pistol propellant by mistake is most likely the culprit.YMMV
5744 appears to be very similar to 4227. Similar burn rate and similar VMD. I have 4227 on hand already. 7.62x39 is not a shoulder breaker anyway, I'm just playing with cast bullets and reduced load. May try the 123 gr cast in 308 which takes 14 gr Trail Boss and gives me the speed!
Just want to be safe when I load only16 gr 4227 in 7.62x39!
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Orcon
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ArchAngelCD
Member.
I don't know what flashover is so I can't answer that question.
4227 is probably one if the fastest rifle powders there is.
You went from a true medium speed rifle powder in 4895 to a really fast rifle powder 4227. Why not pick something in between? Maybe H335 or RL-7. I'm told the New CFE-Blk is a very good choice and designed for that class of cartridges.
4227 is probably one if the fastest rifle powders there is.
You went from a true medium speed rifle powder in 4895 to a really fast rifle powder 4227. Why not pick something in between? Maybe H335 or RL-7. I'm told the New CFE-Blk is a very good choice and designed for that class of cartridges.
That's a good idea. 5744 is good stuff, and bulky.
In response to the original question....Pressure excursion events are generally believed to be confined to greatly reduced charges/low volume density loads of powders slower than IMR 4350. No worries with 4227 and lots of good info in the preceding posts.
someguy2800
Member
It can happen with faster powders than that. I had it happen with benchmark in a 223 a few grains below starting load.
someguy2800
Member
I was loading a reduced load for a 223 handi rifle. I started at hodgdons starting load and worked down in 1/2 grain increments shooting 5 round groups for accuracy. Starting load showed no pressure signs. As charges reduced the primers were flattening out. At 2 or 3 grains below starting I had primers that were alarmingly flattened and cratered, more so than I have ever seen without a blown case, and had to push the gun on my knee to extract the brass. I pulled the bullets on the rest of them and checked the weights and they were all right on. Charges were weighed on a Lyman gen 6 powder dispenser and double checked on a redding beam after the fact. I had benchmark to use up so I loaded a couple hundred just above starting load and shot them all with no drama.
ArchAngelCD
Member.
First off starting loads are just that, not below.
You can not fool physics, extremely high pressures need a fuel source. Without enough powder you can not generate enough pressure to go over pressure. There is just no fuel to generate the volume of gas to create the pressure.
I'm still not sure why you went so much below the starting charge?
You can not fool physics, extremely high pressures need a fuel source. Without enough powder you can not generate enough pressure to go over pressure. There is just no fuel to generate the volume of gas to create the pressure.
I'm still not sure why you went so much below the starting charge?
someguy2800
Member
Because I wanted to. Lots of people do reduced loads. As to not being possible to go over pressure due to low charge weight I guess I will let you explain that to my primers and brass.
ArchAngelCD
Member.
You gota love this new world we live in. Express an opinion other than what someone wants to hear and they become confrontational. I won't be explaining anything or bothering your perfect little world any further.
There is a possibility to be considered here. With inappropriate too light loads of some slow burning powders, the initial primer surge and poor ignition due to slow pressure rise can cause the bullet to leave the case and stop after a short travel into the bore, as the fire ALMOST goes out. Now you have both a bore obstruction and a problem as a secondary pressure rise spikes behind the well stuck bullet. All bets are off at this point, and here is the reason to avoid unpublished light loads of slow burning powders. There are plenty of safe and published reduced loads using appropriate powders to suit just about any purpose.
someguy2800
Member
You came off with a condescending tone as if you were talking down to me suggesting I don't know what I am doing. I apologize if I misread your intentions but I don't think I did.
GooseGestapo
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Sounds like you have a lot of headspace.
Firing pin pushes case foward, igniting powder. Pressure rises, primer backs out to face of bolt. Further increase in pressure sets case back to bolt face reseating primer. Stretched case and flattened primer give indication of high pressure when none exists. (Burnishing of case head, flattened primers and stiff extraction).
Partially full length size cases, just bumping the shoulders.
Should eliminate problems.
I frequently see this loading light loads with cast bullets in old lever action rifles.
Headspace off the shoulder of the case. Will eliminate problem.
I use Benchmark. Mostly in .222 benchrest type loads. It's a relatively fast burning powder. Seriously doubt you are seeing "flash over" unless you are using VERY LIGHT charges. In that case, be VERY CAREFUL of double charges, or even triple.
Firing pin pushes case foward, igniting powder. Pressure rises, primer backs out to face of bolt. Further increase in pressure sets case back to bolt face reseating primer. Stretched case and flattened primer give indication of high pressure when none exists. (Burnishing of case head, flattened primers and stiff extraction).
Partially full length size cases, just bumping the shoulders.
Should eliminate problems.
I frequently see this loading light loads with cast bullets in old lever action rifles.
Headspace off the shoulder of the case. Will eliminate problem.
I use Benchmark. Mostly in .222 benchrest type loads. It's a relatively fast burning powder. Seriously doubt you are seeing "flash over" unless you are using VERY LIGHT charges. In that case, be VERY CAREFUL of double charges, or even triple.
Sounds to me like low pressure.
Firing pin pushes case forward, igniting powder. Pressure rises, primer backs out and flattens against face of bolt. Not enough pressure to set case back to bolt face and reseat primer. Protruding primer makes it difficult to open break-open action.
Firing pin pushes case forward, igniting powder. Pressure rises, primer backs out and flattens against face of bolt. Not enough pressure to set case back to bolt face and reseat primer. Protruding primer makes it difficult to open break-open action.
But some powders don't download well, you have to be careful when downloading.
I'm with GooseGestapo on this one.
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