f*********n 发帖数: 11154 | 1 今天去靶场测试了两个308win的配方,一个用43.1 grain的Varget,另外一个43.2
grain;其他的参数如弹头重量,弹壳牌子等等都是一样的。
43.1gr的前后一共做了50发,回国前去靶场打了20发;今天打了30发。这10个5发组都
很稳定,个人觉得用这个配方我的技术水平对精度的影响大于配方的差异,需要继续勤
修苦练。这个配方已经基本上定为未来一段时间的标准配方了,但是又做了20发43.2gr
的子弹来继续测试。
今天遇到的问题是,这20发子弹中有6发击发以后,将枪栓往上推准备退弹壳时,枪栓
需要花费很大的力气才能开锁;开了以后退弹壳却没有任何阻涩。换上43.1gr的子弹就
没有这个现象。在靶场打得顺序是10发43.1gr的,然后10发43.2gr的(3发出现这个问
题),然后10发43.1gr的,再10发43.2gr(又有3发),最后以10发43.1收尾。
如果说装药量产生的压力已经接近上限的话,退弹壳也应该会遇到一些阻力才对吧?各
位老兄对这个有什么看法或者建议? |
c**********d 发帖数: 2428 | 2 My personal experience is that 0.1gr will not make any difference. |
M*******n 发帖数: 1165 | |
f*********n 发帖数: 11154 | 4 应该不是润滑的问题,之后的43.1gr的就没有这个问题。0.1gr的确不应该有这么大的
区别,但是6/20就基本确定了不是某个弹壳有问题,所以我很奇怪。 |
c**********d 发帖数: 2428 | 5 Have another thought about this. How many time have you reloaded these
casings? If the bolt is heavy but ejection is smooth, then the casing might
be elongated. Watch for ring marks on the case. If they are presented, then
time for it to go. |
f*********n 发帖数: 11154 | 6 这些弹壳每个都是复装了2次,每次装药前都trim过,不过倒是没注意弹壳上面有没有
痕迹,回家以后得看看。 |
c**********d 发帖数: 2428 | 7 Then I think you need to watch out on the shoulder area if the OAL is under
control.
BTW, I remember there is one incident happened to me once. Since your load
is close to the maximum, with 175GR bullet, you may compress the powder to
the case. It happened to me once that the pressure from compressed load is
so large that the neck area is deformed. I can't even chamber the round in
the range. |
f*********n 发帖数: 11154 | 8 刚才把6个弹壳仔细检查了一遍,没有ring mark,但是用caliper测量neck,比其他的弹壳厚了
一点点,长度也略微长了0.02-0.03英寸。
另外就是43.2gr的火药离neck虽然还有一些距离,我算了一下距离,应该是有一点compressed。
6个弹壳有5个是Prvi Partizan的,1个是Federal Gold Medal Match。记得以前听版面上谁
说过PPU的弹壳比较薄,可能就是43.2gr的药量产生的压力把弹壳撑变形了。
刚才拿了两个弹壳,neck sizing了一下,然后重新trim过,上膛和退膛立刻就顺当了。
under
load
powder to
load is
round in
【在 c**********d 的大作中提到】![](/moin_static193/solenoid/img/up.png) : Then I think you need to watch out on the shoulder area if the OAL is under : control. : BTW, I remember there is one incident happened to me once. Since your load : is close to the maximum, with 175GR bullet, you may compress the powder to : the case. It happened to me once that the pressure from compressed load is : so large that the neck area is deformed. I can't even chamber the round in : the range.
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a***a 发帖数: 8941 | |
f*********n 发帖数: 11154 | 10 枪是Savage 10FPXP,308 Win,175 grain Sierra Match King HPBT。弹壳用的是Prvi
Partizan,Federal Gold Medal Match, 和American Eagle打过的弹壳。
【在 a***a 的大作中提到】![](/moin_static193/solenoid/img/up.png) : 什么枪? : 弹头多重?
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