Winchester 296 for Subs?

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Ryno785
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Winchester 296 for Subs?

Post by Ryno785 »

I will preface this with the fact and I brand new to reloading and the price of 300BLK rounds got me into this a few months ago in anticipation of getting my suppressor which I was FINALLY able to pick a couple weeks ago after an ~11 month wait so bear with me....

I have been using 10.8 grains of Accurate 1680 with 220 grain Berry's bullets and a Winchester standard small rifle primer and everything has been working perfectly. My pound of 1680 is gone and I have an 8 lb tub of W296 sitting here that I picked up after reading it was supposedly the same as H110 which seems to widely used for subs. I have been researching it a bit before I loaded up my first few to test and I have seem multiple sources mention that 296 is not ideal for subs as it is easy to exceed maximum pressure levels with reduced charge load but don't understand why? Both Sierra and Hornady show it as an option for their 220 and 225 grain bullets. Hornady shows 6.9-10.9 charges for their 225 and Sierra shows 10.2 to 12.3 for the 220. Both using a Winchester small rifle primer.

What am missing? Is it overly sensitive to temperature changes and could potentially get dangerous in warm weather?
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dellet
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Re: Winchester 296 for Subs?

Post by dellet »

296/h110 can get a little erratic with low density charges so stick with the higher end of published data.

It’s harder to work with than 1680, but you will find it noticeably cleaner and quieter, so in my opinion worth the hassle.

When I say harder to work with, what I mean is sometimes it’s harder to get the load to cycle reliably and stay sub sonic in longer barrels. Carbine length gas systems might add to that. If it all I had, I’d make it work.
It’s actually my go to sub powder for a 10.5” carbine gassed barrel.
300 Blackout, not just for sub-sonics.
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Walkers Bay
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Re: Winchester 296 for Subs?

Post by Walkers Bay »

Im running 296 with SubX projectiles through a shortened suppressed ruger ranch rifle and getting consistent 1040-1080 fps loads with hornady brass and cci 450s.
Without checking my data I think its 9.4gr
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bangbangping
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Re: Winchester 296 for Subs?

Post by bangbangping »

Ryno785 wrote: Wed Dec 22, 2021 3:05 pm ... it is easy to exceed maximum pressure levels with reduced charge load but don't understand why?
Likely what you're referring to is something called "flashover" or Secondary Explosion Effect (SEE). These are not the same thing but are often used interchangeably. The idea is that a reduced powder charge of certain fast powders can detonate rather than burn, completely ruining your day. There is much debate about the cause, likelihood, and even existence of flashover, and as far as I can tell nobody has the real answer. Personally, I don't worry about it, but suggest you do your own research.
Ryno785
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Re: Winchester 296 for Subs?

Post by Ryno785 »

dellet wrote: Thu Dec 23, 2021 12:15 am 296/h110 can get a little erratic with low density charges so stick with the higher end of published data.

It’s harder to work with than 1680, but you will find it noticeably cleaner and quieter, so in my opinion worth the hassle.

When I say harder to work with, what I mean is sometimes it’s harder to get the load to cycle reliably and stay sub sonic in longer barrels. Carbine length gas systems might add to that. If it all I had, I’d make it work.
It’s actually my go to sub powder for a 10.5” carbine gassed barrel.
Appreciate the responses guys. I borrowed a chrono and was finally able to shoot a few different charges through it. All of this was done in relatively cool weather (50-60 F) so I am assuming that is why I am seeing speeds a little on the low side compared the published load data? All charges were measured with a RCBS Link Dispenser and the primers were Winchester small rifle.

220 Berry's over 9.0 grains of 296 (COL: 2.150")
1. 867
2. 899
3. 887

220 Berry's over 9.5 grains of 296 (COL: 2.150")
1. 949
2. 926
3. 929

220 Berry's over 9.8 grains of 296 (COL: 2.150")
1. 965
2. 957
3. 964

220 Hornady round nose over 10.8 grains of 1680 (COL: 2.103")
1. 791
2. 790
3. 769

190 Sub-X over 9.6 grains of 296 (COL: 2.050")
1. 989
2. 985
3. 984

Curious to try again in warmer weather to see how much velocities increase. Really surprised that the 1680 velocities were that low but I need to get back out to chrono some 220 Berry's over 1680 so it's a more legit comparison to my 296 loads. I have some CFE BLK getting delivered today that I will play with as well. Seems to have mediocre reviews but it was in stock so I jumped on it.

Glad to hear that 296 is cleaner as I really surprised at how dirty the gun was after only ~100 rounds with 1680. I have only had my can for a couple weeks now so I just assumed that's how it was going to be running suppressed with a DI gun. The gun ate everything just fine and never missed a beat. I was happy about that after reading about feeding issues with the Hornady round nose and Sub-X bullets.
Ryno785
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Re: Winchester 296 for Subs?

Post by Ryno785 »

bangbangping wrote: Thu Dec 23, 2021 12:31 pm
Ryno785 wrote: Wed Dec 22, 2021 3:05 pm ... it is easy to exceed maximum pressure levels with reduced charge load but don't understand why?
Likely what you're referring to is something called "flashover" or Secondary Explosion Effect (SEE). These are not the same thing but are often used interchangeably. The idea is that a reduced powder charge of certain fast powders can detonate rather than burn, completely ruining your day. There is much debate about the cause, likelihood, and even existence of flashover, and as far as I can tell nobody has the real answer. Personally, I don't worry about it, but suggest you do your own research.
Interesting. Hornady load data shows 8.9 grains of 296 for a 225 grain at 1100 FPS. Sierra load data shows 10.2 grains of 296 for a 220 grain at 1050 FPS. Hodgdon shows 9.2 grains for 220 grain at 1046 FPS.

Strange to me that there is such a wide range of data. Per my testing with the chrono, I think the Sierra load data is closest to what I actually saw. Out of my 8" barrel anyway.
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dellet
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Re: Winchester 296 for Subs?

Post by dellet »

Ryno785 wrote: Wed Dec 29, 2021 2:33 pm
bangbangping wrote: Thu Dec 23, 2021 12:31 pm
Ryno785 wrote: Wed Dec 22, 2021 3:05 pm ... it is easy to exceed maximum pressure levels with reduced charge load but don't understand why?
Likely what you're referring to is something called "flashover" or Secondary Explosion Effect (SEE). These are not the same thing but are often used interchangeably. The idea is that a reduced powder charge of certain fast powders can detonate rather than burn, completely ruining your day. There is much debate about the cause, likelihood, and even existence of flashover, and as far as I can tell nobody has the real answer. Personally, I don't worry about it, but suggest you do your own research.
Interesting. Hornady load data shows 8.9 grains of 296 for a 225 grain at 1100 FPS. Sierra load data shows 10.2 grains of 296 for a 220 grain at 1050 FPS. Hodgdon shows 9.2 grains for 220 grain at 1046 FPS.

Strange to me that there is such a wide range of data. Per my testing with the chrono, I think the Sierra load data is closest to what I actually saw. Out of my 8" barrel anyway.
You might want to check out some articles about the effects of barrel length on velocity.

With supers the difference between an 8" barrel and a 16" barrel can be over 200 fps. With subs it's not than much, but it makes a difference.

All published load data for 300 Blackout will be based on a 16" barrel.

Unless the powder is incredibly temperature intolerant, 1fps per degree is probably a good rule of thumb.
300 Blackout, not just for sub-sonics.
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