Jump to content

A Couple of Groups


Recommended Posts

Just a couple of groups from my day at the range. Both were shot using reloads consisting of 155 grain SMK bullets over 42 grains of IMR 8208 powder in Federal cases with CCI Benchrest primers.

 

100 Yards

 

post-1350-0-57758200-1302213266_thumb.jpg

 

That's seven shots out of a total of ten. The group is approximately one inch wide. Of the other three, two went way high, and the other was pulled low to the right. The two that went high were the first in their respective magazines. My rifle was doing this all day and I have no idea why. Any thoughts would be appreciated.

 

200 Yards

 

post-1350-0-47139100-1302213297_thumb.jpg

 

That's six shots, out of eight. The first two were high, then I adjusted down and got this group. As you might expect, it's probably a little more than two inches wide. This was the last and best group I got at two hundred yards. Dispersion in previous groups seem to have been the result of a loose handguard. This was fired right after I tightened it.

  • Like 2
Link to post
Share on other sites

The first round was hand cycled?

If so it could be a difference in seating of the case and bolt due to lower closing speed.

 

I have noticed it in the past with my groups, I'm not sure how it could be eliminated if this is the cause.

Link to post
Share on other sites

Nice shooting. Have you had any luck with the 155 Amax? I might give that a try next.

 

I usually either single load each round or fire the first shot in a mag at something else. If you switch mags with one still in the chamber you can skip the first hand-cycled round.

 

How long were you waiting between shots and between mags? Could it be a heat issue?

Edited by Dudethebagman
Link to post
Share on other sites

I haven't used the 155 grain A-Max bullets. I don't know how similar their shape is to the Sierra - which is specifically made for Palma rifles, where a 1:13" twist isn't unheard of.

 

As for barrel cooling, I was taking at least thirty seconds between shots and letting the barrel cool completely between magazines.

Link to post
Share on other sites
  • 2 weeks later...

Just shot another group that I thought was worth sharing. This is ten shots at 100 yards (I pulled one low and left). The load used was the same, except for the primers. Who would have thought they could make this big a difference?

 

post-1350-0-30915400-1303340529_thumb.jpg

Link to post
Share on other sites

Finally got to do some load development today with the 155gr Amax and had two loads under 1 MOA for 3 shots, and under 2 MOA for 5. Way better than before. The barrel trim and brake really made a difference. With some more time to fine tune the load I have no doubt it would likely shoot close to 1 MOA for 5 or 6 rounds. But less than 2 MOA for 10 is all I need, and I think I'm there.

Link to post
Share on other sites

Very impressive groups! What primers did you use on the group that opened up? I need to find out what load my 308 likes (it's a 16" gun). What surprised me is the groups were the same (2-3" at 100yds) regardless of whether I was using federal gold match 168gr or some cheap surplus 147gr ball we picked up a few years ago.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
  • Chatbox

    Load More
    You don't have permission to chat.
×
×
  • Create New...