My new rem 7mm mag not a shooter

[jeffro]

You may look into a stiff Laminate stock, they will have an ADL. You can get them where you finish them, and they are priced pretty good.

[mason a]

I'm Hoping to get my gun back early next week, with pillars, glass bedded and floated.so this weekend I worked up another 20 different loads, each 4 shot loads, it will take a full day to go through all the testing because I need time in between groups to let the barrel stay cool.

My question is do I continue to shoot all of my loads at 200 yards, our am i better off at 100 yards to get my data?

[jeffro]

The farther out you can hold dead on the better the test will be. At distance you can also do an OCW test, and see where your rifle likes to be shot as far as the Vel. goes. I do most of my load Del. at 500yrds. It has always worked good for me. If you want a 1/2 MOA rifle, you will have to be able to shoot 1/2 MOA at what ever distance you choose.

[mason a]

The farther out you can hold dead on the better the test will be. At distance you can also do an OCW test, and see where your rifle likes to be shot as far as the Vel. goes. I do most of my load Del. at 500yrds. It has always worked good for me. If you want a 1/2 MOA rifle, you will have to be able to shoot 1/2 MOA at what ever distance you choose.

What is an OCW test?

[308Nut]

OCW stands for 'optimum charge weight'

 

Take note of the 3 groups with bold arrows pointing at them. 46.0 was the best group during this ladder/OCW test. If you notice, the center of the groups from the 45.5 and 46.5 charges are nearly identical to the center of the 46.0 load where the rest of the loads have a center of group that is further away. The plus sign represents the center of the 46.0 load is in reference to each other group. The circles indicate where the center of the actual group is. The closer the circle is to the plust sign the better. Notice how the circle and plus sign with the 45.5 load is dead on in the exact same spot as 46.0 in relation to their targets. This is a good 'harmonic node'. This is what you are looking for. Typically, when you change your charge weight, the groups will shift in relation to the target center. When a good harmonic node is found, groups of slightly different charge weights will hang in the same spot. The 45.0 group is further to the right than the 45.5, 46.0 and 46.5. After these, they begin to move further to the right. With every 1/2 grain increment, the groups move to the right. Also notice how the 48.0 load has opened way up. This illustrates how far out of the harmonic node that bullet/powder/charge weight has become.

 

Sometimes you have to take these kind of results with a grain of salt. After you find your OCW, you should load some more up and go back to the range. If you can duplicate the group or close to it, then it has proven itself. After shooting a 5 shot group the next day using 46.0, the groups measured just over .3" at 100 yards. That told me that it was the real deal. a few days later, 700 yards told the end of the tale. 5 bullets in a 4" group.

 

[jeffro]

I do my OCW test at 500-800yrds. Depending on the gun. Shooting at the same dot the whole time it is very clear as to where your rifle likes to be. They will all be clumping into one area.

[mason a]

You guys are great , thanks for all your help.

At first I thought I was going a bit overboard with so many different load configurations, but now i think I have not gone far enough.

With these next loads that I have ready to shoot, I focused more on powder charge then the seating depth,Now I'm thinking I need to add a few more loads where I change up the seating depths in addition to different powder charges.I think once i get close I will be able to work with smaller increments, and really be able to utilize that ladder test.

BTW that was a great illustration of OCW. Once you find the perfect powder charge can you do the same type of test for your seating depth? If you were to focus on one or the other, as your developing the load, would it be powder charge or seating depth?

Also do you notice your bullets start to do funny things as the barrel starts to heat up? And how do you determine when you need to let the barrel cool down?

Sorry one more question, I have about 20 zip lock baggies with 4 bullets in each bag,with all the load info written on the bag ,then I write the velocities on the bag , then I put that target in that bag corresponding with those bullets shot at that target, But my question is during those 80 shots how often should I clean my barrel?

[jeffro]

Dont clean your barrel. Most barrel will shoot better when fouled. If you clean it, it will shoot differently for a while. All barrels are different though. I clean when the accuracy starts to be affected, or if the barrel gets rained on. If you barrel is a factory, I would start with a fairly clean barrel, as they dont go as far as most customs. As far as heat on your barrel. Dont let it get hot at all. Shoot a group, then let it cool all the way back down. If you cant touch the barrel it way to hot.

[308Nut]

When I am load developing, I like to clean every 20 rounds or so. How ever many you decide on, after it has been cleaned, you will need to run a couple of foul shots using the same powder AND bullets that you will be testing before you begin your tests. Let cool after fouling and fire your 3 shot groups. As mentioned, let it cool completely before trying another group. If you switch to a different bullet manufacturer or type of bullet or type of powder, you will want to start from a clean barrel and foul with those components.

 

Once I have a good load, I will only clean as often as the rifle tells me to or before switching to a different load.

 

As far as seating depths, I dont typically play with that very much. On the lands, off the lands etc.....It's generally not that big a deal espescially when using a factory Remington which has a ton of freebore to begin with. Some bullets can be finicky and will help some more than others. If you start with the standard SAMMI OACL and can only milk close to acceptable accuracy but not quite acceptable, then it may be time to play with the depths. Take your best load and run them .020" out and see if that makes a difference. If not, run them out another .020 so on and so forth. If you have a max load at SAMMI lengths where your rifle has alot of freebore and then run them into the lands, high pressures will likely happen. If you have a max load .020" off the lands to begin with and then jam them into the lands the difference is VERY minimal. Minimal enough to not have to worry about it.

 

Before all of that though, you should start with a given bullet and a given powder. Keep everything to SAMMI specs. Run ladder tests. If you cant find a load under 1 MOA then try the same bullets with a different powder. After 3 powders, try another bullet with the same 3 powders.

 

After that, take your best and try and fine tune it. Up and down .2 of a grain, seating depth and even neck tension using an S type bushing neck sizing die with different size bushings. You should have at least .002 neck tension. Optimum accuracy will vary from load to load and rifle to rifle. Start with .002 and work up to .005.

 

Make sure your primer flash holes are de-burred, primer pockets uniformed, case mouths chamfered, etc......

 

Be sure and test your best loads at 200 or better yet, 300 yards before you give up on them. It happens quite often that a 1 MOA 100 yard load can be a real gem of a load at 300 yards.

 

If after all of that you still are not happy, it may be time to invest in a custom barrel.

 

Keep us posted.

[roninflag]

7mms-one of mine is a sendero/ krieger barrel ; the other is a 1968 adl 24". the 215gm primer gave higher veloctiy and higher pressure and higher sd. Everything shot good in the krieger/sendero. some real good especially the 168's. i have shot a lot of 139 horn as high as 3275 with h-4831( 69.0) in the adl. thought that load was was great; until i shot 140 berger and 140 accubond about a month ago. i use h-4831 and h-4831sc. usually rem9.5m primers. i will have to check amount of powder, it was around 3200fps. 200 yards the adl shot less than 2". one group at one hundred went into .112; 140 accubond and 140 berger.