300BlkTalk

rb288 wrote: ↑Tue Dec 24, 2019 9:47 am

fancygunz wrote: ↑Sun Dec 08, 2019 1:56 am

rb288 wrote: ↑Sat Mar 02, 2019 11:27 am Ok, so, I have been playing with this bullet for a while now, and am just starting to get it figured out.
However, it has raised a few questions.
I am shooting RAR 16" rifle and getting excellant groups, 1 moa or better @100 yds, with, 20.0, 21.0, and 23.0 gns of CFE BLK.
My only "issue", and I may be overthinking this, is that my velocities aren't what I think they should be.
Meaured with a Magneto Speed they are as follows, average for 5 round groups....
20.0 gn....1845 fps
21.0 gn...1959 fps
23.0 gn...2117 fps

The best group was the 21.0 @1959 fps, a .75moa group, the other 2 groups were at 1moa.
Am I being overly "velocity crazy"?

@rb288, what COAL were you using for these loads? Were you able to fit within max SAAMI length?

I used 2.180 oal for these loads in my Ruger American Ranch.
I believe 2.260 is max oal for the 300 blk.

Depends on what you are shooting, 2.260" SAAMI to reflect AR magazine length. This bullet will hit lands around 2.290" depending on how you prep your brass and chamber length.

I was wondering why all your pics were not posting.
I got 3 boxes of the Speer GD 150 BLK OUT bullets the other day.
initial testing at 50 yards gave less that favorable groups, but I forgot I had stock issues (barrel is not free floating anymore after new sling swivels were put in).





I am going to switch stocks and reshoot. Prob will be after Christmas

Remington 700 bolt action
1:7.5 twist Douglas barrel at 16.5"
old 300/221 chambering (had this gun 14 years now)
Will be using A1680 between 22.0 grn - 23.0 grn and 2.180" - 2.200" OAL

Just got back from the gun club, and got a little work done. I had to restock the Camo 700 since the smith that installed the new sling swivels, didn't take into account the heavier barrel I was using, and the barrel rubs. I tried to Dremel some of the bedding out, but I hit the alum plate, and I didn't have the tools to take it down any more, so I grabbed a Magpul Hunter stock I had sitting in the corner, and placed the action in it. No bedding, so fitting, just plain jane factory stock.



I took some fired Lapua brass, dumped some 1680 in there and stuffed some Speer 150grn Gold Dot BO at 2.200" OAL.
Since 22.5 shot pretty good even with the barrel hitting the stock, I loaded up 20 of those to do initial sighting in, and to play at 200 yards should I have a few extra left over. It took 1 shoot to get it on paper, then just moved it to get it close at 100, so I had 19 rounds left.
First I shot a group of 5 with the barrel and suppressor already warmed up. They grouped VERY NICE.... 2100 fps.


After that, I let the barrel cool down, and I did the final scope movement, and shot 3 shot groups after that. THIS IS WHERE I GET PISSED!!!!!
So.... Same load as before, but with the scope adjusted... I got "COLD BORE SYNDROME". The first shot of all these are WAY off.... not a little.... but WAY off.... You can easily tell in the pics. I shot these two groups back to back, so the second target doesn't have a cold bore shot.

Now I decide to do the ladder testing with loads from 21.0 - 23.0 grains. With my seating depth at 2.200" the 23.0 grains is forcing the bullet out of the neck, so I abandoned that powder charge, and only went to 22.6.

My chrono reading were:
21.0 1960 fps
21.3 2000 fps
21.6 2040 fps
22.0 2040 fps
22.3 2090 fps
22.6 2110 fps

My initial plan was to shot 3 shot groups, and let the barrel cool 8-10 minutes in-between groups.
so after I shot all those 22.5 loads, I waited 8 mins. and on target 1 (bottom left corner) you can see the first cold shot is low. Not too bad.... so I et the barrel cool another 8 mins.
On target 2, you can see a HUGE shot low. So I shot group 3 (top left) immediately after group 2 (after I moved the scope down 1 moa) and I didn't let the barrel cool off. no cold bore shot, and the group is decent.

I let the barrel cool between 3 and 4 (top right), but then shot 5 and 6 immediately after without cooling.



I clicked 1/2 MOA right into the scope and left it right there, and took the last 8 rounds I used as my control group to the 200 bench.
I stacked 2 targets on top of each other so I could see actual drop in impact. It dropped approx. 8" and had a cold bore low shot, however I was very happy with that load, and plan on doing more testing in this node and playing with seating depths.

Don't give up the fight

Wonder about the cold bore shift being velocity related. A relatively slow powder and a suppressor full of O2, might be worth a check.

This was posted on the first page and shows a slight adjustment on length. I do a lot of short range work up because I can shoot at home.

dellet wrote: ↑Tue Apr 24, 2018 11:38 am Six shots at 50 yards, one inch dot for reference.



Six more shots after .005" seating depth adjustment. Note they are inside the previous six



Bright evening sun with a 5-7mph wind coming from about 10 o'clock.

dellet wrote: ↑Fri Dec 27, 2019 7:56 pm Don't give up the fight

Wonder about the cold bore shift being velocity related. A relatively slow powder and a suppressor full of O2, might be worth a check.

[/quote]

How would I combat that?

P1ZombieKiller wrote: ↑Fri Dec 27, 2019 9:50 pm

dellet wrote: ↑Fri Dec 27, 2019 7:56 pm Don't give up the fight

Wonder about the cold bore shift being velocity related. A relatively slow powder and a suppressor full of O2, might be worth a check.

How would I combat that?

There’s a couple way’s to verify and a couple things to try.

You can verify shooting without the suppressor and confirm it by shooting a round with it on and then covering the covering the muzzle end with taper. This keep a minimal amount of air going in.

Getting rid of it can be more of a problem. Getting a better burn on the powder is generally more pressure but you’re probably close to maxing out. That playing with seating depth or crimp can help.

Going to a faster powder can also be helpful.

First is to see if it’s even an issue.

I loaded up a few more yesterday and decided to see if there was a difference in the LC brass over the Lapua. Man was I surprised.
I wont bore you with all the pictures, but the LC brass did as good or better than the Lapua brass. I knew between 22.0 and 22.5 is where I should be. Turns out 22.2 in the LC brass looked very well at 100 in initial testing. I plan on tweaking the seating depth a little more.

My loads are listed on the targets. What I also noticed is that the LC did a little better at 200 yards, and the posted BC of 460 seemed to be pretty on for me the day of testing based on JBM saying 7.9" drop, and I got 7" of drop at 200 with my 10 shots (but my 3 shots are slightly higher at 100 than a true 100 yard zero).

I have loaded up 50 at 22.5 and plan on doing a little hunting with them this weekend. No pigs on my place, but maybe I will take a deer, and can post entrance and exit wounds.

Rifle:
Remington 700 Trued action
16.5" Douglas barrel with SWR Omega 30 supressor
Magpul stock with Magpul bottom metal and detach mag
Vortex Gen 2 scope 5-25
EGW 20 moa rail with TPS rings

Well that should at least slow a zombie down some if nothing else.

Any improvement on first round flyer?

The 200 yard group almost looks like two strings, was it all same load and time?

LC converted brass can be very good, only other thing I can think of might be a different primer. But it sure looks like it keeps getting better. Basic MOA isn’t a terrible start.

Look forward to the hunt results

I also found the LC brass to work very well, though the primer pockets seem to start to get fairly loose after 3 firings of supers. Still usable, just noticed the change, which seems to appear after similar Subs firings. I have a theory...Maybe Dellet can 'splain why that may be. I have used Nosler, Win, RP, WCC and a few others and always had good supers results. So far, 1680 has been best with the 150 Gold Dot, CFE being pretty close and N120 showed promise. When it warms up to near 40* here, the down slope winds and wind chill make shooting/chrony work about a waste of components...frustrating. Nice work OP, enjoy your dedication to the craft