I'm using imr 4064 in 308 mil brass. The powder is already compressing at 40.6 . I want to work up to 42.6. Is this going to be a problem compressing powder like this.
Compressing powder
- Thread starter ChitownCopper
- Start date
J F Johannes
AKA "RatRifle"
If you can't get 40.6 gr of IMR 4064 in a .308 case without compressing, something is seriously wrong. DON'T DO IT. Figure out what's wrong.
Jim
Jim
I can hear it slight crunch when seating the bullet
Need more info. What bullet? What seating OAL?
Military brass may have less case capacity?
The Hodgdon website shows a compressed maximum load with ALL bullets, using IMR 4064 powder.
https://www.accurateshooter.com/cartridge-guides/308win/
See 308 Winchester Load Map
2.800 hornady match 178
i agree with Jim. Something isn’t right. Need more info. I just loaded a bunch of 165 SGK using 42.3g of 4046 and an OAL of 2.800. Bullet nowhere near compressing the load
It's very common to hear the boat tail on the Hornady 178gr match crunch the powder as it's seated when using IMR 4064, 40.0 grains is right about when you'll use up 100% of the usable volume. 42.6gr is a top end load (compared to SAAMI specs) but it's doable without causing any damage to the rifle or the shooter.
I doubt that your 40.6gr load is all that compressed, maybe 1 or 2 percent with the 42.6gr load producing approximately 6% compression. That's more than I like but it's not terrible.
The problem with compressing any load is that you might find that the bullet will push back out (due to the compressed powder pushing on the base of the bullet) over time and the cartridge overall length will then vary.
Personally I quit using IMR 4064 quite a while ago, just about any other commonly recommended powder will work better. A few powders that would give you the same velocities and accuracy would be IMR 3031, IMR 4895, and BL (C2). All of those powders will produce about the same velocity as 42.6gr of IMR 4064 using less powder and without creating a compressed load. I use IMR 3031 quite often (around 40.2gr of IMR 3031 will produce velocities equivalent to the 42.6gr IMR 4064 load), it is just as accurate as the other good powders and very accurate if you are happy with the slower nodes.
I doubt that your 40.6gr load is all that compressed, maybe 1 or 2 percent with the 42.6gr load producing approximately 6% compression. That's more than I like but it's not terrible.
The problem with compressing any load is that you might find that the bullet will push back out (due to the compressed powder pushing on the base of the bullet) over time and the cartridge overall length will then vary.
Personally I quit using IMR 4064 quite a while ago, just about any other commonly recommended powder will work better. A few powders that would give you the same velocities and accuracy would be IMR 3031, IMR 4895, and BL (C2). All of those powders will produce about the same velocity as 42.6gr of IMR 4064 using less powder and without creating a compressed load. I use IMR 3031 quite often (around 40.2gr of IMR 3031 will produce velocities equivalent to the 42.6gr IMR 4064 load), it is just as accurate as the other good powders and very accurate if you are happy with the slower nodes.
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OP is right.
Since I was already set up and loading .308 I just tried his load using the Hornady ELD-M with 40.6g of 4064 seated at 2.800. It does indeed crunch at the end of the stroke
Since I was already set up and loading .308 I just tried his load using the Hornady ELD-M with 40.6g of 4064 seated at 2.800. It does indeed crunch at the end of the stroke
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J F Johannes
AKA "RatRifle"
You guys need to read through this post to see where I am coming from. In that post he was attempting to load 168gr Match Kings, now he is on to Hornady 178gr.
http://forum.accurateshooter.com/threads/new-to-reloading-need-a-mentor.3990293/
Jim
http://forum.accurateshooter.com/threads/new-to-reloading-need-a-mentor.3990293/
Jim
You have to recognize that the crunching you are hearing is the powder granules being broken as the tapered boat tail is pushed in to the powder. The boat tail creates a cone shaped space between it and the case wall and the powder is being pushed up in to that small space.
Most any time that you compress a powder you'll get worse velocity SD numbers due to changing the burn characteristics of the powder. If you are breaking the granules then you are exposing more surface area to the flame front as the powder burns. That changes the burn rate of those broken granules. Add variation of the bullet seating depth (due to the bullets being pushed out to some random distance by the compressed powder - unless you crimp (which can create higher than normal chamber pressures), and you can see that your cartridge performance will vary quite a bit and very randomly - that's not what you want for accuracy.
Most any time that you compress a powder you'll get worse velocity SD numbers due to changing the burn characteristics of the powder. If you are breaking the granules then you are exposing more surface area to the flame front as the powder burns. That changes the burn rate of those broken granules. Add variation of the bullet seating depth (due to the bullets being pushed out to some random distance by the compressed powder - unless you crimp (which can create higher than normal chamber pressures), and you can see that your cartridge performance will vary quite a bit and very randomly - that's not what you want for accuracy.
In my Lyman book says 44
Yes I have multiple weight bullets that I will load at different poder weight to see what shoots best out of my rifle
True. My commercial brass load is 43.6
Once again, when you read a reloading manual EVERYTHING has to be the same in order for the load recommendations to be the same - and they aren't.
Look at the specs that they publish about the loads that they test, the case brand and preparation are probably different, the device used to test the load is probably different (universal receiver or an actual rifle, if a rifle which one?). On top of that, when were the loads developed? Hogdon's printed manuals are terrible, they are a mix of load developments from decades ago to current times from a variety of sources. One 168gr boat tailed match isn't the same as another, the shape of the boat tail will create differences in usable volume inside the case and that will create different pressure and velocities. And in the end, everyone's chamber is slightly different and that will create variation in what load works best for your rifle.
Just saying that a manual publishes the max load to be some amount doesn't mean much if you don't compare how they built that load to the load that the shooter is using.
Look at the specs that they publish about the loads that they test, the case brand and preparation are probably different, the device used to test the load is probably different (universal receiver or an actual rifle, if a rifle which one?). On top of that, when were the loads developed? Hogdon's printed manuals are terrible, they are a mix of load developments from decades ago to current times from a variety of sources. One 168gr boat tailed match isn't the same as another, the shape of the boat tail will create differences in usable volume inside the case and that will create different pressure and velocities. And in the end, everyone's chamber is slightly different and that will create variation in what load works best for your rifle.
Just saying that a manual publishes the max load to be some amount doesn't mean much if you don't compare how they built that load to the load that the shooter is using.
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