Pressures with different powders

Demaiter · February 13, 2009, 10:35 AM

Alright guys, my lyman manual shows a compressed load for the 69 grain sierra matchking in .223

It is using varget powder and the pressure is said to be only 40,000. Why is it 5-000 to 10,000 lower than ever other powder used? If I shoot a load that is say 50,000 what will my difference be in barrel life? Will my barrel last 20% longer assuming I don't burn it out by shooting huge amounts of ammo really fast?

dlb435 · February 13, 2009, 03:15 PM

Powders have different burn rates. Faster powders will give you higher pressures than lowers speed powders. There is also the burn temperature and how much ash is produced. First, check your barrel. Is it 223 REM or is it 5.56 NATO? 223 REM barrels are good for a max pressure of 55,000 and the 5.56 NATO barrel is good for 62,367. Keep that in mind when developing a load.
Varget is not a very dense powder. To get enough in the case you have to compress the charge. A 69 grain bullet is larger than the 55 grain bullet so you lose some case space to the larger bullet. The lower pressure is from that reduced charge. The great thing about Varget is that you almost can't over charge the case. Unlike some other powders that only fill the case 2/3 the way.
I hope that helps.
I don't believe that higher pressures reduce barrel life. (as long as they are below the rating for your barrel) Good gun care makes all the difference. It is almost imposible to find corisive primers or powders these days.

Demaiter · February 13, 2009, 04:08 PM

thanks for that info, that makes sense, a faster burning powder will have more pressure as it builds up and burns quicker. My barrel is a standard .223 barrel. I'm going to be using H 335 because varget is sold out everywhere with 69 grain sierra match kings - I'm following the lyman 49th load in the manual.

Shoney · February 13, 2009, 04:26 PM

Demaiter
Not meaning to be derogatory here, but my data shows a load of 69 grain Sierra Matchking__Varget__ (min load) 24.0__39,200CUP---- (max load) 26.0C__50,200CUP.

Is it possible that you read the minimum load pressure instead of the max???

HJ857 · February 13, 2009, 04:30 PM

I just switched from H335 to Reloder 15, more versatility with heavier bullets and works just fine with my basic 55 grain bulk soft point loads. Natchez has it in stock as well. RL15 is worth a look, lots of the high power crowd go with RL15 over Varget due, seemingly, to better velocity.

Demaiter · February 13, 2009, 07:53 PM

Quote:

Demaiter
Not meaning to be derogatory here, but my data shows a load of 69 grain Sierra Matchking__Varget__ (min load) 24.0__39,200CUP---- (max load) 26.0C__50,200CUP.

My Lyman 49th edition manual shows 23.4 grains as min @ 33,700 C.U.P and max it shows - 26.0+(+ means compressed) @ 40,500 C.U.P

I found it unique too which is why I am posting about it. All the other loads are around 50,000 - anyone think its a typo?

February 13, 2009, 10:35 AM	#1
Demaiter Senior Member Join Date: October 27, 2008 Posts: 242	Pressures with different powders Alright guys, my lyman manual shows a compressed load for the 69 grain sierra matchking in .223 It is using varget powder and the pressure is said to be only 40,000. Why is it 5-000 to 10,000 lower than ever other powder used? If I shoot a load that is say 50,000 what will my difference be in barrel life? Will my barrel last 20% longer assuming I don't burn it out by shooting huge amounts of ammo really fast?

February 13, 2009, 04:26 PM	#4
Shoney Senior Member Join Date: February 21, 2002 Location: Transplanted from Montana Posts: 2,311	Demaiter Not meaning to be derogatory here, but my data shows a load of 69 grain Sierra Matchking__Varget__ (min load) 24.0__39,200CUP---- (max load) 26.0C__50,200CUP. Is it possible that you read the minimum load pressure instead of the max??? __________________ I pledge allegiance to the Flag - - -, and to the Republic for which it stands….Our Forefathers were brilliant for giving us a Republic, not a democracy! Do you know the difference??? and WHY?http://www.wallbuilders.com/LIBissue...les.asp?id=111

February 13, 2009, 03:15 PM	#2
dlb435 Senior Member Join Date: January 26, 2009 Posts: 654	Powders have different burn rates. Faster powders will give you higher pressures than lowers speed powders. There is also the burn temperature and how much ash is produced. First, check your barrel. Is it 223 REM or is it 5.56 NATO? 223 REM barrels are good for a max pressure of 55,000 and the 5.56 NATO barrel is good for 62,367. Keep that in mind when developing a load. Varget is not a very dense powder. To get enough in the case you have to compress the charge. A 69 grain bullet is larger than the 55 grain bullet so you lose some case space to the larger bullet. The lower pressure is from that reduced charge. The great thing about Varget is that you almost can't over charge the case. Unlike some other powders that only fill the case 2/3 the way. I hope that helps. I don't believe that higher pressures reduce barrel life. (as long as they are below the rating for your barrel) Good gun care makes all the difference. It is almost imposible to find corisive primers or powders these days.

February 13, 2009, 04:08 PM	#3
Demaiter Senior Member Join Date: October 27, 2008 Posts: 242	thanks for that info, that makes sense, a faster burning powder will have more pressure as it builds up and burns quicker. My barrel is a standard .223 barrel. I'm going to be using H 335 because varget is sold out everywhere with 69 grain sierra match kings - I'm following the lyman 49th load in the manual.

February 13, 2009, 04:30 PM	#5
HJ857 Senior Member Join Date: January 9, 2007 Posts: 447	I just switched from H335 to Reloder 15, more versatility with heavier bullets and works just fine with my basic 55 grain bulk soft point loads. Natchez has it in stock as well. RL15 is worth a look, lots of the high power crowd go with RL15 over Varget due, seemingly, to better velocity.