Hey all. I just finished up doing some seating depth testing on my Remington 700 .243 Varmint rifle and figured it would be a good idea to post my methods and my findings on here. I like to do a lot of testing and I also like to help and share whatever I find and experience with others. I often recommend to others to test their seating depth. It can very much change your group size and your results as you will see below.
Before I get into my results, I'd like to explain my methodology and how I go about this test. First, I'd like to say every bullet is going to have preferences to bullet jump. There's the thought that certain bullets are less sensitive than others, and that may be true, but in my testing and experience it seems they all can be tweaked to shoot their best. I highly recommend everyone to go over to the Precision Rifle Blog and read their latest articles on bullet jump and the results that Mark Gordon of Short Action Customs and other top shooters have found and tested. That is a very good read and it really opened my eyes up to test seating bullets even further from the lands than I ever did in the past. I'd also like to say, this is for guys who want to shoot at 100 yards or may only have access to 100 yard ranges most of the time. I have to travel an hour or longer to get to places that I'm able to shoot 300+ yards. I use this method to find good results at 100 yards where I'm able to shoot year round and is only 5 minutes from home.
When I go about doing seating depth, I first find my lands by using the Wheeler method. There's a video on YouTube of Alex Wheeler demonstrating and explaining it. I will then load rounds up in .010 increments from say .020 off to .100 off. I like to load 3 at each length to shoot a group of 3 to better represent what they'll actually shoot like. I have tried this with two shots and have seen others do it with one, but 3 gives you an average and a true group. For the test I did today, I just started 3gr below max in my new Peterson brass and shot the seating depth test. In my experience and the experience of others, if you have the right bullet jump, you can shoot any powder charge and your sweet spot in bullet jump will stay the same. I have experienced this in multiple rifles of my own and friends, and have seen the data from others to back this up.
There are also ways to fine tune your seating depth when you're closer to the lands by adjusting in .002-.003 increments. The problem with having a load close to the lands is that it can be very sensitive to change. If you have a hot magnum you may erode the throat .005-.010 in 100 rounds. Then you have to keep chasing the lands. Finding a more forgiving bullet jump "node" like I show below will result in good groups even with some throat erosion. There may be a sensitive seating depth that shoots even better, but I find it annoying to have to chase the lands. So this is why I look for a window in seating depths that give good results and are not as sensitive.
Today I shot groups from .030 off the lands to .100 off. These were all shot with virgin Peterson .243 brass, 87gr VMAXs, 41.0gr IMR 4451, and Winchester Match primers. I took a few minute break between each group to let the barrel cool and to not get uncomfortable or fatigued behind the rifle. I started with a clean barrel and fired 3 rounds from my previous load on the bottom right target. That group was very good, but this load has some pressure signs in warmer weather and the ES is a little higher than I'd like. I then adjusted my scope down and put one in the center just to return to zero. Today's test was mainly looking to see if I could improve on anything and to just do some more testing for fun and for data.
Here are my results. Starting from top left is .030 off and ending with .100 off on the third target on the bottom row. My conclusion is .090-.100 off looks really good and will be where I do some further testing. I will say I feel like I pulled one shot today and that was the lower impact on the .090 off group. I'm very happy with that .100 off group and the couple other good ones I shot today. This rifle sure hammers for a factory Remington with some bedding and handloads!
Before I get into my results, I'd like to explain my methodology and how I go about this test. First, I'd like to say every bullet is going to have preferences to bullet jump. There's the thought that certain bullets are less sensitive than others, and that may be true, but in my testing and experience it seems they all can be tweaked to shoot their best. I highly recommend everyone to go over to the Precision Rifle Blog and read their latest articles on bullet jump and the results that Mark Gordon of Short Action Customs and other top shooters have found and tested. That is a very good read and it really opened my eyes up to test seating bullets even further from the lands than I ever did in the past. I'd also like to say, this is for guys who want to shoot at 100 yards or may only have access to 100 yard ranges most of the time. I have to travel an hour or longer to get to places that I'm able to shoot 300+ yards. I use this method to find good results at 100 yards where I'm able to shoot year round and is only 5 minutes from home.
When I go about doing seating depth, I first find my lands by using the Wheeler method. There's a video on YouTube of Alex Wheeler demonstrating and explaining it. I will then load rounds up in .010 increments from say .020 off to .100 off. I like to load 3 at each length to shoot a group of 3 to better represent what they'll actually shoot like. I have tried this with two shots and have seen others do it with one, but 3 gives you an average and a true group. For the test I did today, I just started 3gr below max in my new Peterson brass and shot the seating depth test. In my experience and the experience of others, if you have the right bullet jump, you can shoot any powder charge and your sweet spot in bullet jump will stay the same. I have experienced this in multiple rifles of my own and friends, and have seen the data from others to back this up.
There are also ways to fine tune your seating depth when you're closer to the lands by adjusting in .002-.003 increments. The problem with having a load close to the lands is that it can be very sensitive to change. If you have a hot magnum you may erode the throat .005-.010 in 100 rounds. Then you have to keep chasing the lands. Finding a more forgiving bullet jump "node" like I show below will result in good groups even with some throat erosion. There may be a sensitive seating depth that shoots even better, but I find it annoying to have to chase the lands. So this is why I look for a window in seating depths that give good results and are not as sensitive.
Today I shot groups from .030 off the lands to .100 off. These were all shot with virgin Peterson .243 brass, 87gr VMAXs, 41.0gr IMR 4451, and Winchester Match primers. I took a few minute break between each group to let the barrel cool and to not get uncomfortable or fatigued behind the rifle. I started with a clean barrel and fired 3 rounds from my previous load on the bottom right target. That group was very good, but this load has some pressure signs in warmer weather and the ES is a little higher than I'd like. I then adjusted my scope down and put one in the center just to return to zero. Today's test was mainly looking to see if I could improve on anything and to just do some more testing for fun and for data.
Here are my results. Starting from top left is .030 off and ending with .100 off on the third target on the bottom row. My conclusion is .090-.100 off looks really good and will be where I do some further testing. I will say I feel like I pulled one shot today and that was the lower impact on the .090 off group. I'm very happy with that .100 off group and the couple other good ones I shot today. This rifle sure hammers for a factory Remington with some bedding and handloads!
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