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Hot Topic (More than 10 Replies) How do you figure out the compression (Read 4425 times)
dogman
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How do you figure out the compression
Feb 2nd, 2012 at 7:35pm
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Another  no  way the really know question.

Is there any way to figure out about how much
compression to use on the powder charge?
Is there any danger of over compressing?

And I suppose it all depends on the brand of
powder as well...My powder is Goex 2F. And  I suppose it will change from one lot to  another.. Tongue Tongue.
  
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gunlaker
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Re: How do you figure out the compression
Reply #1 - Feb 3rd, 2012 at 11:03am
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I put a wad on the powder and use the depth guage on my calipers to measure the distance from wad to case mouth.  Then I compress and measure again. The difference is the amount of compression.  I don't use as much as some people. My loads run from zero to maybe 0.4".  I don't load based on the amount of compression, but rather on the powder charge weight.  The compression takes care of itself.

Chris.
  
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art_ruggiero
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Re: How do you figure out the compression
Reply #2 - Feb 3rd, 2012 at 11:16am
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i take a sample bullet of the one i will load,  sand or turn the base bands down a small amount so it slides freely into the sized case and then measure over all length before and after compressing the powder  art
  
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dogman
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Re: How do you figure out the compression
Reply #3 - Feb 3rd, 2012 at 2:23pm
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sounds like a great why to measure it..I will try that myself..Thanks for the idea..
  
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MikeT
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Re: How do you figure out the compression
Reply #4 - Feb 3rd, 2012 at 10:33pm
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dogman,

If you bulge the case, you have just applied too much compression.

Keep on hav'n fun!
MikeT
  
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dogman
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Re: How do you figure out the compression
Reply #5 - Feb 4th, 2012 at 7:49am
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I was reading an article last night that I found on the internet where the guy claimed that Goex should not be compressed more than 1/8 of an inch...Somthing about all the fines in the powder?
  
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MikeT
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Re: How do you figure out the compression
Reply #6 - Feb 4th, 2012 at 8:51am
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I do know of actual people who do not compress any powder very much and get good results, it just has not worked for me with Goex.  For example, my 40-82 win; last month I experimented with Fg Goex Express.  Filled case [about 86-88 grains], compressed 0.325 to the bottom of the case neck [40-82 has slight bottle neck], set a 1/8" cork wad under a PP bullet of 430 grains, then neck sized the case to hole the bullet securely.  I shot that load at 1K and did much better than I should have considering the low tech loading method and a bullet that is not stable a 1K.   

Keep on hav'n fun!
MikeT
  
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SchwarzStock
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Re: How do you figure out the compression
Reply #7 - Feb 6th, 2012 at 2:31pm
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I use the caliper method to measure the powder compression and have found powder quality makes the biggest diference in the amount of compression required. Schuetzen requires the most followed by Goex while Swiss needs little to none. I have had some lots of Wano (Schuetzen) that required well over 0.350" to get anything close to a clean burn. It was actually Wano that caused me to develop duplex loads.

When shooting PPB,s I charge the case, compress the powder, insert a wad, insert a disc of wx paper, insert a disc of lube and then seat the bullet by pushing it into the case using the nose in a hole I made in the front of my loading bench for that purpuse. I do not use the seater stem in my taper crimp die as that could apply additional compression and later the bullets base or perhaps cause lubrication to be pushed into the powder charge and contaminating it.

For GG bullets I omit the lube disc but all else remains the same,

SS
  
If your rifle is not in 7.62 and you can't hit what you are aiming at with de-linked machinegun ammo you are a pretender.
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John Boy
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Re: How do you figure out the compression
Reply #8 - Feb 6th, 2012 at 2:43pm
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John, here is a reading for you to learn more about reloading BPCR's ... (You need to Login or Register to view media files and links)

1. Introduction
2. Special Equipment
a. Drop Tube
b. Bullet Molds & Nose Punch for Lubesizer
c. Lead Melting Pot
d. Lubesizer
e. Compression Plug
f. Scale(s)
g. Blow Tube
3. Components
a. Brass Wads
b. Primers
c. Powder
d. Bullets
e. Indexing
f. Lube
4. Loading Techniques
a. Powder & Compression
b. Bullets
5. Shooting
a. Working Up a Load
b. Use of a blow tube
6. Load and shooting records
7. Favorite Loads
8. Loading for the 45-70 “Trapdoor” by “Minnesota Al”
  
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westerner
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Re: How do you figure out the compression
Reply #9 - Feb 6th, 2012 at 3:10pm
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MikeT wrote on Feb 4th, 2012 at 8:51am:
I do know of actual people who do not compress any powder very much and get good results, it just has not worked for me with Goex.  For example, my 40-82 win; last month I experimented with Fg Goex Express.  Filled case [about 86-88 grains], compressed 0.325 to the bottom of the case neck [40-82 has slight bottle neck], set a 1/8" cork wad under a PP bullet of 430 grains, then neck sized the case to hole the bullet securely.  I shot that load at 1K and did much better than I should have considering the low tech loading method and a bullet that is not stable a 1K.  

Keep on hav'n fun!
MikeT


Since going back to basics a couple years ago, I have not tried GOEX uncompressed.  Goex Express and Swiss is what I've been shooting lately.   

I think a little compression does increase consistency when applied to GOEX 1 2 &3F

        Joe. 
  
A blind squirrel runs into a tree every once in a while.
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macca
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Re: How do you figure out the compression
Reply #10 - Feb 10th, 2012 at 8:06am
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Hi, 
I use calipers to determine my compression (currently 150thou). I shoot Wano 2P that has been socked (polishes powder and removes dust), case cleaning water barely discoloured. 
Im actually becoming more interested in seating depth. Increased my depth by .005 inch and have found an improvement in accuracy (all other load factors the same) Some of my F class friends have a jump of 25 thou to get their 1/4 inch groups. My current load  are at 5 thou shall try 10 thou next week. 
Cheers macca Smiley
  
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