Lithgow Crossover LA102 load dev and disassembled pics

[Jimbo047]

I wanted to share some results from my efforts in developing a load for my Lithgow LA102 Crossover 223. I am a new shooter and thought my results might be interesting for others like me.

First, here are some pictures:

Complete:

Action, left:

Action, right:

Action, bottom:

Bolt face:

Safety:

Bolt:

Stock, entire:

Stock, inlet:

I decided to start with the Sierra 55gr GameKing bullets (SuperRoo 1000 box - pretty cheap and definitely realistic for bulk hunting rounds). First of all, I wanted to know where the maximum pressure was plus fireform a bunch of cartridges. ADI reckoned that a bullet like this would be 24-25.6 grains of Benchmark 2 so I started at 24 and went up to 26 in 0.2 grain increments. I started seeing pressure signs at 25.6 and stopped at 25.8.

I then measured the water volume of the fireformed cases (30.15 grains) vs the full-length sized cases I did the pressure test with (29.95 grains). These were once-fired Sako headstamp which I put through a FLS die, trimmed, and neck turned.

Quickload reckoned that the fireformed case would take about an extra grain to reach the same pressure. I wanted to find something toward the top of the pressure gradient so I started the fireformed test at 25.5 and went up to 27.0, measuring velocities with a MagnetoSpeed Sporter:

Node:

I liked 26.0. I next wanted to test seating depth variation. The last test had supposedly been seating at 0.03 from the lands but I had noticed a bunch of variation in the overall length (measured at the ogive). I measured the bullets using a comparator and found considerable variation (who'd have thought with a pack of budget hunting rounds, huh?)

So I carefully loaded up a bunch of 26.0 grain rounds to a few different seating depths: lands, 0.015, 0.030, and 0.050:

Depth velocities:

And here are the actual targets:

Repeat 1:

The main group top right contains four holes at 0.15 MOA with the flyer corresponding to the round with increased velocity in the depth comparison chart at 0.03 - interesting!

Repeat 2:

I realise that this is super nerdy. But I'm a scientist so this is the sort of thing I enjoy. And anyway, I'm getting just starting out and am having a blast doing it.

If people are interested I can post a similar writeup of some higher quality target projectiles in a couple of weeks. The verdict on the Lithgow? Fantastic. Easily sub-MOA. Above was all on a front and rear sandbag.

Can't wait for them to announce a 6.5 Creedmoor.

[Apollo]

Don't know why you would have pulled it apart but ... interesting.

I love your approach to the load testing. I do not like the idea of a Magnospeed simply for the idea of something hanging off the barrel that's not going to be there in general use. I do use a Chrony but velocity readings are just a simple comparison from one load to another in my view. Once I get a rough idea I give up with any interest in velocities.

The result on the target is what counts, be it target shooting or just general varminting / hunting. Ignore the flyer as you have done, the next test was different and shows a very good result.

55gr bullets in a .223Rem are a good combination with ADI Benchmark 2 and have shown to me in a number of different rifles very good to fantastic accuracy. The fiddle with seating depth is the fine tune.

Sierra are a pretty good bullet maker but not in the ballpark of the likes of Berger Bullets when it comes to consistent results for not that much if any extra cost. Maybe I am biased shooting Berger's in competition but even general use that is all I buy these days. In bulk so I have a huge reserve supply. Money well spent. Anything from a .22 Hornet to 6.5mm has been the best performance I have seen for the results I want, which is consistent accuracy and velocity typical of less than 1/2 MOA from a factory rifle.

Never owned a 6.5 Creedmoor but then I was more towards target shooting so I picked a better performer in 6.5x47 Lapua of which I have three, a Tikka T3, Remington 700 and a Custom made Stolle. My initial thoughts were from reading a number of comparisons of 260Rem, 6.5 Creed & the 6.5x47L which in my view won overall and for me and some friends certainly shines at 500 Metre Competition.

Looking further to more of your results and thoughts and wish you all the best. Did I say "I love your thinking"...

Keep it up.

[Apollo]

BTW....

Looking at group shooting to give the best accuracy overall, look at the groups that do not have a lot of horizontal spread. A bit of vertical is good for the reason that if you have some wind it will stay a bit tighter to be on target than the load that has horizontal which will only go further horizontal.

If you are only a hunter / varminter then after you find your good load go and test.. first shot difference in point of impact.

[Jimbo047]

Thanks for the advice. I'll look into getting hold of some Berger bullets. My goal with this round of testing was to get a load that performed consistently to let me move on to practicing field positions, knowing that poor results were mine rather than the rifle or load. I think I'm there.

I do understand the concern about the MagnetoSpeed on the barrel. I'll do a +/- test next week for a point of impact shift and let you know what happens.

I don't really have a thing for 6.5CM either. I just think it is inevitable that this will be their next calibre.

Oh, and I pulled it apart because… Well, I don't know really. I just like to know how things work.

[Gwion]

One of the members here was kind enough to loan me his magneto speed. I found its effect on group size was minimal. Just reconfirm your group side and POI after gathering your velocity data. The smallest group will still be the smallest group, or it was for me.

[Cooper]

I'll be interested to see what POI shift you get when the Magneto speed is removed. I got a bigger shift in point of impact from running the Magneto speed than I did running a muzzle break. Didn't really seem to effect group sizes just verticle shift. Witnessed the same effect on 22lr, 223 and 7mm 08. No idea if it is just barrel harmonics or something else.

[Gamerancher]

Looking at those targets, I'd stick with the 26gr, .030" loading. That one flyer that went high was obviously just that.
Now that you have your load, go shooting.

[Xerox]

Quality looking bit of gear

[Gwion]

Thanks for the advice. I'll look into getting hold of some Berger bullets. My goal with this round of testing was to get a load that performed consistently to let me move on to practicing field positions, knowing that poor results were mine rather than the rifle or load. I think I'm there.

I do understand the concern about the MagnetoSpeed on the barrel. I'll do a +/- test next week for a point of impact shift and let you know what happens.

I don't really have a thing for 6.5CM either. I just think it is inevitable that this will be their next calibre.

Oh, and I pulled it apart because… Well, I don't know really. I just like to know how things work.

By the way, Jimbo: i also started my 223rem loading with BenchMark2 but switched to BM8208 and found it to be more consistent and tightened the groups right up. The BM2 load averaged about 0..5-0.7moa and the BM8208 took it down to a consistent 0.4moa, reducing flyers and both horizontal and vertical dispersion. When i put it over a magnetospeed the velocities where very consistent shot to shot and group to group.

[Jimbo047]

By the way, Jimbo: i also started my 223rem loading with BenchMark2 but switched to BM8208 and found it to be more consistent and tightened the groups right up. The BM2 load averaged about 0..5-0.7moa and the BM8208 took it down to a consistent 0.4moa, reducing flyers and both horizontal and vertical dispersion. When i put it over a magnetospeed the velocities where very consistent shot to shot and group to group.

Huh, interesting. I was really torn between 8208 and BM2. I'll give it a go - thanks

[Gwion]

By the way, Jimbo: i also started my 223rem loading with BenchMark2 but switched to BM8208 and found it to be more consistent and tightened the groups right up. The BM2 load averaged about 0..5-0.7moa and the BM8208 took it down to a consistent 0.4moa, reducing flyers and both horizontal and vertical dispersion. When i put it over a magnetospeed the velocities where very consistent shot to shot and group to group.

Huh, interesting. I was really torn between 8208 and BM2. I'll give it a go - thanks

There were, I'm sure, other factor contributing such as small accurising steps taken on the rifle and me getting better at pulling the trigger but I switched after others told me that they had found 8208 to be the best for their 223. I made the switch and found the same. It's at least worth a go if you are chasing those tight and consistent groups.

[Drewvic]

By the way, Jimbo: i also started my 223rem loading with BenchMark2 but switched to BM8208 and found it to be more consistent and tightened the groups right up. The BM2 load averaged about 0..5-0.7moa and the BM8208 took it down to a consistent 0.4moa, reducing flyers and both horizontal and vertical dispersion. When i put it over a magnetospeed the velocities where very consistent shot to shot and group to group.

Huh, interesting. I was really torn between 8208 and BM2. I'll give it a go - thanks

I've just started playing with 8208 in my lithy so I'd be interested to hear how you go with it.

[Supaduke]

+1 on the 8208 for .223, i get very good results.