compressed loads

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skizzums

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can someone explain the dangers to heavily compressing a load? and the reasons why it's is or isn't recommended? I am loading 125gr Hornaday SST 300BLK with IMR 4227. 17.8gr of powder. hornaday manual shows up to 18+, but I don't see it possible. this is just a poor powder choice overall for supersonic 300, but I have a good bit and trying to get over 2000fps. but I am just curious, manual shows that this will be compressed, which I am use to compressing 4064 in .223, but not this hard.

if it's not a safe thing to do, I can back off a grain, but performance will suffer greatly, as I have already don't work-ups on this bullet with little gun and found it's sweet spot to be between 2k and 2100. thanks for any insight
 
Well I will throw this out to you to try and see if it helps or not.

Down at your local hardware store or possibly laying around your shop if you are like me, find you some brass tubing which is a touch smaller in diameter than the mouth of your case. Longer is better but you get into being able to reach and dump issues.

Sometimes a picture is worth, well you know the saying,
Drop Tube Pic's

All your trying to make here is a drop tube long enough for the powder to fall in at a more random rate than simply being poured in through the funnel sitting atop the case. This gives it a chance to settle better and allows more space when it does. Another thing you might try is using an engraver, and touching the sides of your loading block while the charged cases are sitting in it. You might set a piece of cardboard over the top first to keep the powder from vibrating out, but this has dropped the level in some of my past loads almost 1/4" from being right up to the lip of the case mouth.

On the drop tube you might start long and cut it back to what works the best. With the other, there are plenty of other things that can work to settle the powder, heck even tapping on the side of the case as you slowly pour in the powder helps.
 
I use a 24" drop-tube while loading black powder rounds, works great
for me and a drop-tube will work for you too.

I should mention to that I BELLED my copper tube to fit over the cases. I made
my tube easy to rise by inserting the tube through two eye screws and an
o-ring for a stopper.
 
I am not having a problem getting the powder in there, more just concerned with the act of doing it. does it create a dangerous situation when being compressed? I know they say some powders are worse than others, just wondering why and what's the potential danger.
 
As far as my knowledge goes compression of powder isn't the issue. It is a pressure thing. Meaning about all powders could be compressed in theory as long as it didn't exceed pressures for that caliber while doing so. God Bless
 
I loaded some 40 with some herco powder. In the Lee book the start load is compressed but just slightly judging by bullet depth but is listed as a compressed load. It shot great. Best accuracy for me in my pistol so far right up there with my n340 load. I wouldn't load one just tightly compressed load manuals all unanimously say not to do that but I'm no longer afraid of lightly compressed loads in published data with slower powders. The best part is there's no chance of a double charge if you drop two itll all just spill out.
 
I load ALOT of 300blk.
I use 4227 under a 125gn smk
I dont try to reach max velocities with that combo. Its just not a good fit. If you need max velocities (for a hunting or SD round) use a more suitable powder. W296 or Lilgun come to mind.
I have got GREAT groups out of my 4227 125gn SMK load, but its nowhere near 18 gns of powder. My load fills the case to the top of the shoulder and leaves the neck free for the bullet. Sub MOA outta my 9" AAC upper with a 1-4 scope
 
I know I cant get near max velocities, or even close to max pressure due to capacity. I just want to be right at 2k, which I should be with the current load. just wondering if compressing powder too much is DANGEROUS or could cause other potential problems.

I was shooting 100gr lapua's cutting edge with lil gun in 300BLK. great load, never had an issue, but it was really compressed. was told by a couple other not to compress lil' gun..... just wondering why it's okay for some powders and not for others and what problems does it create.
 
As long as load calls for compressed loads, it shouldn't be an issue as long as you stay within data and workup.

My match loads are compressed loads. Great accuracy. I look for loads using complete case fill or C max loads.
 
Compressed loads have two problems.

They've never shot bullets as accurate as loaded round case capacity charged via drop tubes.

Powder particles start to crack from pressure against others. That changes each particle's burn rate. The more that are cracked and broken, the more inconsistent the charge burns. So does peak pressure vary as it goes higher.
 
I agree with the breaking of grains, I know I can hear the crunch when compressing 4064. I can't help but think that this 4227 isn't going to be broken down any farther though, not from simple compression at least. but it doesn't sounds as if though I am going to get any bad reaction from it. I was thinking maybe pressure spikes or other issues could be a possibility, but I haven't heard that being the issue from anyone. as for accuracy, I haven't found a load as accurate for ME than compressed 4064 in a 77gr .223. I have about 300 of those SMK's to load up right now, maybe i'll invest some time in a tube this weekend an see if I can get any better results.
 
I use IMR 4064 for 308, never had the need to compress the load. I would be carefull with the brass, compressing Winchester or Remington brass your charge may work, but using Federal, the brass is thicker & using the same charge amount, you would have to reduce your load. What is the need to compress?
 
There's almost no away to put enough 4064 in a 223 case without compressing. I use it for my highpower loads and fps is important. Compressing 4064 a bit doesn't concern me, being such a long grain powder, their is enough empty space leftover not to cause pressure problems. Plus, the powder will break and conform before the case does
 
I've found that my slightly compressed match loads give me better consistency. Verified via chronograph. That's why I get the best accuracy from them.
 
JW, if your compressed loads test 1/4 moa through 200 yards, 1/3 at 300 and 1/2 moa at 600 yards, all with 10-shot groups, that's amazing. That's what non-compressed loads can do.
 
Well, those are about what I get if I do my part.

Last time just to check I shot a 3-shot at 100 yards and got .141" center to center spread. Not to bad I'd say.

My 10 shot groups I get about what you laid out, with a SD of 5 and ES of 9-10.
 
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