More 350 Legend...

[44Blam]

Went to the range today with some loads of Norma 200 and some loads that were Acc 36-180 YG and Acc 35-125 YG.
Turns out a FULL case (slightly compressed) made those boolits go THE SAME VELOCITY...

So the 180s are about 2000 fps with 28 grain and the 125s are a little plus 2000 with 29.5 grain. But 29.5 grain filled the case up to about 1/8" from the top of the case!

However, it looks like with Alliant 2400 (according to QuickLoads), I should be able to send those 125 around 2500 fps... Will have to try it next week.

[mehavey]

Lighter bullets -- faster powder.
(Einstein' 9th Law)

[fastdadio]

On the subject of faster powders... When loading for the AR as 44Blam is, and I will be when I get some primers, I think faster powders should be the prefered choice.
The BCA 350 AR comes with a carbine length gas system. This is not how Mr. Stoner originally designed his rifle. We are charting new territory here. The carbine length gas port is only 7 inches forward of the chamber. We need space (barrel volume) for the pressure to spike and fall off some before the boolit passes the gas port in the barrel in order to avoid possibly over gassing the bolt carrier. Which could happen with the slower rifle powders that are best used with the original service rifles.
Just my thoughts on loading for the AR.

[45r]

My 18 inch bca shoots 1 inch groups at 50 yards using 26.7 grains CFEblack under a powder coated 215gc boolit.
Haven't chronographed them but they might be around 1900 fps.

[44Blam]

I am actually looking at trying a 125 grain boolit with Alliant 2400...
I figured out how to make a boolit file (thanks Mehavey). And I made an entry for my Accurate 35-125YG.

Looks like somewhere around 24 grain of Aliant 2400 should get that booger up to about 2500 fps. Looks like small increments will make large changes in pressure, so... Will start low and see if it matches and continue on until I find something nice.

[mattri]

44Blam,
Thanks for the post- what is your intended use?

[44Blam]

44Blam,
Thanks for the post- what is your intended use?

I actually shot some of these originally because I was waiting on my 180 grain boolits to age a bit and I had a whole lot of these guys. I normally shoot these in 357 sig, but they actually shoot really nicely in the 350LG AR. So, I pretty much intend to plink with them but I'm hoping with a little more velocity that I'll get a little flatter trajectory and maybe get a little more distance before it drops.

Currently, with a 100 yard zero the 180 grain boolits drop about 3 MOA at 200 yards and about 7 MOA at 300 yards and then about 18 MOA at 400 yards. So, we went from 21" drop to about 72" drop. I'm assuming it went subsonic between 3 and 400 yards. Hopefully, the 125s hold out a little further.

[mattri]

Interesting, thanks.

Currently waiting on a 350 Legend barrel for a Savage action so looking forward to seeing how this progresses.

[mehavey]

Hopefully, the 125s hold out a little further.

You can use QuickTARGET and run the 125gr ballistics.

Pick any Lyman or RCBS bullet of same weight/shape and start it at your intended muzzle velocity.
Set max Range at 500 and Output for velocity vs range

[44Blam]

You can use QuickTARGET and run the 125gr ballistics.

Pick any Lyman or RCBS bullet of same weight/shape and start it at your intended muzzle velocity.
Set max Range at 500 and Output for velocity vs range

Interesting - the data for the 125 and the 180 are almost the same. However, my actual DOPE on the 180 is different than what QuikcTarget shows...

I have a feeling that this set of computer programs is going to have me shooting more...

[mehavey]

I'm running a LABRADAR and will go back, look, and re-confirrn the 180's BC.
(Apparently you are as well. What BC is your data generating?)

RELOOK UPDATE:

[44Blam]

I did recently get a LabRadar. My old Chrony was a Caldwell and I got a lot of random data -- then when I tried to contact Caldwell, they were unresponsive and then unhelpful.

It looks like my 125s BC is about 0.150 and my 180s are 0.208...
These were calculated with this site: https://www.jbmballistics.com/cgi-bin/jbmbcv-5.1.cgi

I'll do some research on how to calc the BC. Previously, I haven't gotten as technical so I never looked up the calc.

However, my velocities are V0, v11,v22,v33,v44,v55... Maybe I need to RTM and figure out how to get the V100...

[cwlongshot]

I was able to Crowd 2600 fps in my MAXI with a 125 SP bullet. Shouldnt be a issue in the Legend. I did load some when I first got the rifle and quick sited for a couple Coyote hunts but never connected. I dont remember the load but should have been 2500 ish +. Accuracy was 2" range. But I just picked a load and went with it.

I have never seen Norma 200. Id like to try that Acxurate 11fs or some such.

CW

[mehavey]

Maybe I need to RTM and figure out how to get the V100...

BTW: That LABRADAR will track the velocities right through your
target & backer and keep right on recording things down range.

BTRx2: Even the simplest Drag Function (and therefore the Ballistic
Coefficient) is a power function of the velocity at every point in the
change in that velocity
Cd = D / (A * .5 * r * V^2)

But even that's dependent on nose shape, sonic condition, and tail



So "BC" is really more like a black cat in a dark room that has an attitude.
(any of you guys married?)

[44Blam]

Well, Alliant 2400 gave me some interesting #s... I most certainly did not get to 2500 fps and it certainly did not over pressure the round. There were two shots above 2400, but they were on different loads. :-/

Note that this is my load in my firearm with my COL, boolts, etc -- work your own load up.
Here it is:
Shot 1 Shot 2 Shot 3 Shot 4 Shot 5 Avg Spread
Load 1 23 2107 2181 2248 2279 2203.75 172
Load 2 23.5 2245 2358 2437 2282 2425 2349.4 192
Load 3 24 2267 2329 2248 2266 2284 2278.8 81
Load 4 24.5 2382 2270 2411 2260 2357 2336 151


I did not have any major pressure signs even with the higher velocity boolits. However, the lower velocity loads still had very round primers - so very low pressure. Probalby in the 30k range.

All of these were REALLY nice to shoot and had reasonable accuracy. I noticed boolits in either extreme didn't really group well, but kind of expect that. I think I'm going to go a little hotter to see if I start to get more consistent ignition. I think I may also try to use a dacron wad to keep all the powder down at the bottom of the case to see if I can get a little better ignition.

[44Blam]

Oh - one note on sucess.
Note that this is my load in my firearm with my COL, boolts, etc -- work your own load up.
I tuned my Accurate 36-180YG (without lube groves) with 28.2 grn of Norma 200:
2026 2027 2030 2021 2022

9FPS spread. And that load is accurate -- it's my Norma 200 load for sure.

[mehavey]

Norma-200 (like Vihtavuori N-110) is magic stiff