Following Jim’s reloading dope for 6.5cm, I bought 100 rounds of new 6.5cm Lapua brass. Used Hornady 143 ELDX bullets, Federal Champion 205 small rifle primers, 41.2 grains Hodgdon H4350 gunpowder, with a coal of 2.78. According to Garmin Xero Chrono, Average was 2592.4 fps with a std dev of 9.0fps.
At the range I was shooting a Sig Cross 6.5cm, suppressed, with a Burris Veracity PH 4-20x50. Shots were indoors at 100yards. Being 71 years old, i am not as good as Jim, just don’t see as well but at least these are 1" or less. Don’t think I can shoot .25". But since I am a hunter and not a competition shooter, I think I will be ok.
Many guys sight in high at 100 yards to have a better maximum effective range without holding high out to a longer distance. I think of a deer’s vital area as hitting a 8 inch plate. Anything in that area is a great shot. So if your not shooting long range your accuracy is plenty good I think
Actually you did all the work. That is your recipe. But I do have some questions.
I started with new un-fired Lapua brass. Used a Federal primer rather than CCI. Sig Cross 6.5cm just like yours. You made reference to after firing the shoulder on Hornady “d” headspace comparator would be 1.541". All of mine are 1.535" and I haven’t sized any. I have cycled all 25 through the Sig and bolt closes with ease. The case length of all 25 is1.915" which according to Hornady reloading manual should be 1.92. When I loaded the rounds the COAL was 2.78"
So it actually appears that the cases didn’t really stretch. @Backfire any thoughts?
The internal dimensions on the chamber in factory rifles can be 30-40 thousandths difference, maybe more due to different tooling, and the min - max acceptability of the design. The 1.920 also has a window of of - .20 thousandths. I think you are doing fine based on the numbers, and if you are not having pressure issues. Dont know what you loaded up to test your groups, but they are pretty uniform (circular) so the barrel is liking that node. Some times when you have the seperation of 3 shots from 2, or 2 from 1 at the 1.0 inch group size, adding a half grain could close it up for you (or not).
Good luck
You know, if those are 1 inch squares, the top group looks to be closing in on .675 - .725 and the bottom one at .750 - .800. Those are good groups. Assuming you are using the same aimpoint, when you lay them over the top of each other it looks to be pretty close to 1 MOA for ten rounds, very good. Throwing out external variables, 6 x 8 = 48 or 600 yards shooting a .800 group at 100 gives you a 4.8 inch group potential at 600 yards…if you and the rifle are holding that things are working well.
JV
My point was my fired Lapua cases did not appear to have stretched at all. I was able to cycle all the once fired brass to the action of my Sig Cross 6.5cm, and the bolt closed with ease no different than chambering a loaded round. Jim said once fired according to the Hornady head space comparator was 1.541", and to size to 1.539". All of mine are 1.535" and I haven’t sized any. The case length of all 25 is1.915" which according to Hornady reloading manual should be 1.92. When I loaded the rounds the COAL was 2.78".
So really my question is, isn’t it unusual that the cases didn’t stretch? Since the base to shoulder is where it should be, and the length of case is where it should be, does this mean I don’t need to full length resize them? Or maybe just neck size since the neck is larger than the bullet diameter. Or did the case just conform to the chamber and that is why I can chamber the un-resized brass with ease and no heavy bolt to close. I know if I try and chamber a fire 6.5prc or 7prc case it does not chamber with ease. According to my Garmin the average over 7 shots was 2592.4 with a std dev of 9
Check out the winning in the wind YouTube channel. He recently had a discussion regarding once fired brass . It does look like they don’t always fully expand to the chamber dimensions. Reading some other online forms this seems to be more likely if you’re using high-quality, premium, Stiffer brass.
Yeah, it’s pretty common to be able to chamber once fired. Some cartridges and brass designs stretch more than others. Probably will be different after second firing.
Brass doesnt stretch by leaps and bounds generally. If the load you are using is a not right at the high end generating pressure, then even less reason for the brass to stretch. Once fired will almost always chamber easily, but yes the neck must be resized to hold the next bullet. Doing a minimum shoulder bump on a fired case is what allows you to benefit from the case being form fitted to the chamber; makes the case for neck sizing and leaving the shoulder alone, but after a number of firings cases tend to get tighter and tighter even in the same chamber. With my 308s, I rarely even worry about trimming the cases because they have not shown a pattern of stretching for 5-7 firings that I need to worry about. I will say this, yes the Lapua brass is one of the best, and Federal brass is very similar in weight to Lapua; both start to get harder to chamber much faster than Winchester brass (which is thinner). For medium calibers like the 243, 6.5CM, 7-08, and 308, running medium to high pressures, I am not sure that using Lapua is always the cats meow due to the cost these days. Using Winchester for the majority of my loads as a start point has produced very good groups for me; later when I wanted to see if the load could be improved upon, I would migrate over to the Lapua. I assume that the 6.5 PRC and 7 PRC have tighter chambers in factory rifles than other calibers, at least that is what I think I have read regarding those two and it is one of the reasons they are supposed to shoot better with factory ammunition. That makes sense, when I have a rifle rebarreled I will ask for it to be headspaced to a dummy round, which I set at a factory COAL (which is normally shorter than handloads). That has produced rifles for me that when I have to grab as box of factory ammo vs my handloads, it shoots very well due to the minimized jump to the lands. Anyway, you have a good handle on it and tracking the numbers, data, etc., is the way to do it.
Good luck
