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Posted: 6/3/2012 2:51:21 PM EDT
| Loaded some 300 blk 150 grains today. I blew primers at 16.5 grains of H110. Published max is 17.0. I think that the temp (90's) had something to do with it, as well as COAL. I had heard that H110 was a temp sensitive powder and this sure proves it! Accuracy was great! Recoil is hard to portray. It felt the same as the .223 that I shoot (26.5 grains of varget 55 grain) but with more of a push. Like I said, it is hard to explain. As far as COAL, I loaded the rounds to the cannalure, which I think was a little too short. I ordered some 110 grain soft points for hog hunting that I'll be loading up this week. I really like the cartridge. We'll see how well it works on hogs. My AR10 was shooting sub MOA at 100 yards as usual. Have to love that gun! Overall, a great day of shooting. |
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It's ALWAYs hard to wait! I've been able to run H110 up to 18.0 grains with a Hornady 150g FMJBT bullet out of an 11-1/2" barrel. At 18.0 grains, the primer radius was just beginning to flatten out. At 17.5 grains, all is fine. I averaged 1970 fps, range of 41, and an SD of 10 with 20 samples. Shoots straight. Temp was only around 70 degrees when I set them off. I think why I might be getting away with 17.5-18.0 is that it's a 1:11 polygonal twist barrel. I've also loaded rounds at 17.0 grains and averaged 1922 fps. What was your overall length? I've set the above loads at 2.075" OAL with a trimmed case length of 1.358". Case mouth is right in the middle of the cannelure. Brass is mixed Lake City with CCI #41 primers. That is all... |
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so this relates to another recent post http://www.ar15.com/forums/t_6_42/372345_Seating_223_bullets_with_cannelure.htmlregarding oal affecting pressure in bottle neck vs straight walled pistol.
from dryflash " With rifle cases, seating deeper will not increase pressure. The larger volume of a rifle case makes this different than pistol cases. With straight wall pistol cases, seating deeper will increase pressure. A much smaller internal volume with pistol cases is the reason. Compressed load Do Not increase the pressure of a load. If you are dealing with a published load, compressed loads are perfectly safe. Slow burning powders can and will fill the case full. The bullet will crunch the powder when seated. Normal and not a problem. If you have ever loaded Varget in 223 you would know this. With Varget in 223, it's almost impossible to get too much powder in the case to make a high pressure load. It's a slow burning powder when used in 223." Is the 300 really either? |
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Quoted:
so this relates to another recent post http://www.ar15.com/forums/t_6_42/372345_Seating_223_bullets_with_cannelure.htmlregarding oal affecting pressure in bottle neck vs straight walled pistol. from dryflash " With rifle cases, seating deeper will not increase pressure. The larger volume of a rifle case makes this different than pistol cases. With straight wall pistol cases, seating deeper will increase pressure. A much smaller internal volume with pistol cases is the reason. Compressed load Do Not increase the pressure of a load. If you are dealing with a published load, compressed loads are perfectly safe. Slow burning powders can and will fill the case full. The bullet will crunch the powder when seated. Normal and not a problem. If you have ever loaded Varget in 223 you would know this. With Varget in 223, it's almost impossible to get too much powder in the case to make a high pressure load. It's a slow burning powder when used in 223." Is the 300 really either? In general, you're using much faster powders in the 300 than you would be in traditional bottleneck rifle cases, so it behaves more like a pistol round. It's a very slightly taper-walled round with bullets that can be set back way too far. The round wasn't really designed with 150 grain bullets in mind, but there are plenty of people out there using them successfully. You just have to finesse the COL and powder charge, since you're not using the slower powders generally used for subsonics, but you're not using the lighter, shorter bullets generally used for supers. |
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Quoted:
That's a great question! Received my case gauge and all my brass spec'd out fine. The problem is lack of published data for the round. I had no formally published data for the 150 grain pills. Your brass and rounds can all be in spec and you still could have head space issues. If you want to measure the head space on your rifle you need a set of go, no go head space gauges. I run my 147gr pulls 17.4gr of H110 at a COAL of 2.135 a in my Axis. Primers are flat but not flowing. I've read from others posts (that are much smarter than me) that H110 builds pressure rapidly when approaching max loads. Try some Lilgun if you can't get the H110 to work for you. |
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Loading to the cannelure means nothing. The cannelure can be located anywhere and is bullet specific.
What is your COAL for the loaded rounds? What type and brand of bullet? The only info we have to go from is the bullet is 150gr and it has a cannelure that you loaded them to. Need more solid info before good advice can be given. My 147gr pulls. Some load to cannelure some below it some above it. The ogive and brass length determines where the cannelure ends up. 
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Quoted: Seems about right to me. As posted earlier, I'm at 2.075" and they feed and shoot all day using MagPul 20 round mags. No nicks, scratches or dings on the cases. No overpressure; No FTF; No FTE. 20 round chrono sample with a standard deviation of 10 with 17.0 grains of H110. Works for me!2.058 COAL with Hornady 150 grain FMJBT, which was at the low end of the cannalure. Hey, if guys want to load them long... fine. With a boat tail bullet, as you move the bullet out of the neck, less bullet surface area is left to contact the neck. Again... it works for me... your mileage may vary. BTW, the SAAMI spec on overall cartridge length is 1.780" minimum to 2.260" maximum. I think both 2.058" and 2.075" are in spec. Flame if you must. That is all... |
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