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Posted: 10/21/2013 11:31:14 AM EDT
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Would one of you guys with the Quickload program check out the pressure for this load for me?
65gr Gameking 25.9gr Tac 1 x LC brass 2.255 oal 20" Blackhole barrel w/ 5.56 chamber Loaded and shot five of these without noticable pressure signs. I know I am getting near max, but I would like to know an approximate chamber pressure. Thanks. |
Cartridge : 5.56 mm NATO - 5.56 x 45 mm |
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Here is a link to the Ramshot Loading Guide 5.0
For .223 Pressures Max is 24.3 grs OAL 2.210" For 5.56 Pressures Max is 26.3 grs OAL 2.210" You're loading out to a longer OAL so that will lower pressure some. According to the reloading info from Ramshot you can go up to 26.3 grs estimated velocity of 3184 fps out of 24" barrel. So, actual velocity will be a little lower than that with the 20" barrel. |
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Quoted:
Here is a link to the Ramshot Loading Guide 5.0 For .223 Pressures Max is 24.3 grs OAL 2.210" For 5.56 Pressures Max is 26.3 grs OAL 2.210" You're loading out to a longer OAL so that will lower pressure some. According to the reloading info from Ramshot you can go up to 26.3 grs estimated velocity of 3184 fps out of 24" barrel. So, actual velocity will be a little lower than that with the 20" barrel. On the contrary, loading longer will increase pressure in a bottle necked rifle round, not decrease it. The longer the OAL the shorter the jump to the lands, the shorter the jump the higher the pressure. |
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Quoted:
On the contrary, loading longer will increase pressure in a bottle necked rifle round, not decrease it. The longer the OAL the shorter the jump to the lands, the shorter the jump the higher the pressure. Quoted:
Quoted:
Here is a link to the Ramshot Loading Guide 5.0 For .223 Pressures Max is 24.3 grs OAL 2.210" For 5.56 Pressures Max is 26.3 grs OAL 2.210" You're loading out to a longer OAL so that will lower pressure some. According to the reloading info from Ramshot you can go up to 26.3 grs estimated velocity of 3184 fps out of 24" barrel. So, actual velocity will be a little lower than that with the 20" barrel. On the contrary, loading longer will increase pressure in a bottle necked rifle round, not decrease it. The longer the OAL the shorter the jump to the lands, the shorter the jump the higher the pressure. Well if you are jammed into the rifling I can see this happening. Playing with quickload you can see the pressure drop when you increase the OAL. That is until you jam the round into the rifling. The 6.8 SPC guys always load long to reduce pressure so they can get a little more powder in the case. |
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One of the problems with QL is it cannot calculate the distance to the lands or when you are into the lands.
The 6.8 guys redesigned the chamber after Rem screwed it up. They increased the length of the throat to give the bullet a longer jump to reduce pressures. Same with the 223 vs 5.56, longer throat in the 5.56 allowed for higher pressure rounds. From John Barsness of Handloader/Rifle Magazines. It decreases peak pressure, for two reasons. The longer "jump" of the bullet to the rifling results in a lower peak pressure, since the bullet engraves more easily the faster it's going when it hits the rifling. Also involved is the "progressive" burning of almost all modern rifle powders. This means the pressure increases relatively slowly from the time of ignition. Thus peak pressure occurs when the bullet beyond the barrel throat, with very slow-burning powders as much as 3-4 inches. Here are a couple charts for your viewing pleasure. 
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