First go with the 300 BLK
- Thread starter Ian
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Ian
Notorious member
That jump affects the ignition curve a bit, which can be used to the advantage with the right powder. Basically if the powder of choice doesn't light off too quickly, the primer itself does a gentle "breech seat" of the bullet and the big powder "whoosh" happens right when the bullet has aligned itself in the throat.
Using H110 in charges from 15.2 to 15.8 gr I got velocities from 1750 to just over 1800 fps. I was expecting a bit faster. Looking at the brass and velocities I can still go higher.
Groups from the 15.2 and 15.5 gr loads ran 4 inches for 20 shots.
I think the Lee 155 will shoot better than this. These were sized .310 and lubed with BR. I want to see what max for this combination is then try some .311 bullets just to see if it makes any difference.
I also want to seat the bullets a bit longer and see how that changes things. These were crimped just above the top of the lube groove.
Leading hasn't been an issue yet. The BCG doesn't get grungy either. The magazine follower was picking up oil from the BCG but that doesn't bother me a bit. I tend to run my ARs pretty wet.
Groups from the 15.2 and 15.5 gr loads ran 4 inches for 20 shots.
I think the Lee 155 will shoot better than this. These were sized .310 and lubed with BR. I want to see what max for this combination is then try some .311 bullets just to see if it makes any difference.
I also want to seat the bullets a bit longer and see how that changes things. These were crimped just above the top of the lube groove.
Leading hasn't been an issue yet. The BCG doesn't get grungy either. The magazine follower was picking up oil from the BCG but that doesn't bother me a bit. I tend to run my ARs pretty wet.
I have considered it strongly. I will likely pick some up and give it a go.
I'm using Rem 7 1/2 primers now for all shooting in this rifle. They are puncture resistant, a good thing in an AR. When shooting HP competition I ruined a firing pin with Win SR primers. The Rem 7 1/2 and CCI BR 4 primers seem to resist puncture far better.
After firing 200 rounds I will say that I really like the cartridge. Never gonna be a long range hammer but for shooting to 2-300 yards there is a lot to like.
I'm using Rem 7 1/2 primers now for all shooting in this rifle. They are puncture resistant, a good thing in an AR. When shooting HP competition I ruined a firing pin with Win SR primers. The Rem 7 1/2 and CCI BR 4 primers seem to resist puncture far better.
After firing 200 rounds I will say that I really like the cartridge. Never gonna be a long range hammer but for shooting to 2-300 yards there is a lot to like.
I've shot MP300. With the Lee 155 crimped into the front driving band, RP 7-1/2 primers, it grouped pretty well at the upper threshold of pressure. 17.1-17.3 was as hot as I dared go. 15.8gr of my lot of H110 chrono'd 1920fps. One of the local guys crimps the Lee 155 into the crimp groove and shoots 17gr IMR4227. I didn't push H110 or 4227 to the point of ejector swipes and expanded primer pockets like I did with MP300.
Loaded up more of the 30 sil with 1680 and some with H110. I need to cast more of the Lee 155, I don't cast a bunch because I wanted to see how they did first. I hate casting hundreds of bullets then finding they shot like crap.
I also moved the scope forward a little. I want to be able to find a better cheek weld.
I also moved the scope forward a little. I want to be able to find a better cheek weld.
Just got back.
H110 is good in this rifle but 15.9 and 16.2 gr is a bit much with the 30 sil. Shoots well but the ejector marks tell me it is a bit hot.
1680 still does well.
The rifle is teaching me a bunch about bench technique. Shoulder it firm on one shot and it goes 3 inches hit. Free recoil is consistent but I had to remove the rear sling swivel. Learning how to shoot it from the bench is going to take some time and having a really light rifle doesn't make it easier.
I need to cast a bunch more Lee 155s. The shot as well, maybe better. The groups were certainly rounder.
Pounding a 6 inch gong at 100 rapid fire is not at all difficult.
H110 is good in this rifle but 15.9 and 16.2 gr is a bit much with the 30 sil. Shoots well but the ejector marks tell me it is a bit hot.
1680 still does well.
The rifle is teaching me a bunch about bench technique. Shoulder it firm on one shot and it goes 3 inches hit. Free recoil is consistent but I had to remove the rear sling swivel. Learning how to shoot it from the bench is going to take some time and having a really light rifle doesn't make it easier.
I need to cast a bunch more Lee 155s. The shot as well, maybe better. The groups were certainly rounder.
Pounding a 6 inch gong at 100 rapid fire is not at all difficult.
fiver
Well-Known Member
I like to put both hands on a rifle that has a handle, on the handle.
I've taken to doing it on my hunting rifles when sighting them in too.
I wrap the right hand around the grip fairly loose but comfortable and then use the left to pull everything in tight.
it has helped my group sizes quite a bit.
I've taken to doing it on my hunting rifles when sighting them in too.
I wrap the right hand around the grip fairly loose but comfortable and then use the left to pull everything in tight.
it has helped my group sizes quite a bit.
Ian
Notorious member
I gave my 300 another workout today at a friend's ranch. I was testing a new muzzle brake and Cabela's collapsible shooting bipod and he wanted to borrow my Magneto Speed to finish up some subsonic 7.62x39 load development. Ended up running nearly a hundred rounds through mine and shot some groups at 50 and 100 yards. It's still holding 1.5 MOA in a very linear fashion with zero windage fluctuation, but the brake did raise the 100-yard group a bit vs. the A2 flash hider. We didn't shoot it at 25, but it's 3" high at 50 and 1.5" high at 100 whereas before it was dead on at 25 and 100 and about 1.5" high at 50. The more I shoot this thing the more I like it, right now it's one of my favorites.
The main reason I'm mentioning this is I took Fiver's tip above for the bench work and used both hands on the pistol grip. I'm sold on that technique now, it took all the squirminess out of the system (particularly during follow-through) and I felt it really helped my groups. No flyers at all all day, just solid, round groups and lots of busted rocks and soda cans.
The shooting sticks worked pretty well, too, but like most things that are height-specific they're about two inches too short for me. I'm 6' tall, the world is apparently designed around 5'8-10" men. This was the bane of my existence as an automotive technician since lift arm clearance at max height on above-ground hoists is only enough to peel the hide off the top of my skull if I forget to duck.
The main reason I'm mentioning this is I took Fiver's tip above for the bench work and used both hands on the pistol grip. I'm sold on that technique now, it took all the squirminess out of the system (particularly during follow-through) and I felt it really helped my groups. No flyers at all all day, just solid, round groups and lots of busted rocks and soda cans.
The shooting sticks worked pretty well, too, but like most things that are height-specific they're about two inches too short for me. I'm 6' tall, the world is apparently designed around 5'8-10" men. This was the bane of my existence as an automotive technician since lift arm clearance at max height on above-ground hoists is only enough to peel the hide off the top of my skull if I forget to duck.
fiver
Well-Known Member
funny you should mention the muzzle brake changing poi.
I just screwed one on my 300 and in the field it seemed it was shooting high and a tick to the right versus just the muzzle cap I had on it before.
I thought it was maybe because I had to clock the brake a tick past where they said to align the logo.
I noticed missing some jack rabbits on the high side, but only had to click over 1/2" at 50yds.
I just spun the dial down about 20 clicks and kept on hunting, three straight head shots at distances from 25-100 yds confirmed it enough for me.
the brake changed how the rifle sounded too, it was pretty cool to miss and see the rabbit look around like what was that?
they'd then resume eating until I shot at the bottom of their head then flap they went over, and tried running for a bit.
I just screwed one on my 300 and in the field it seemed it was shooting high and a tick to the right versus just the muzzle cap I had on it before.
I thought it was maybe because I had to clock the brake a tick past where they said to align the logo.
I noticed missing some jack rabbits on the high side, but only had to click over 1/2" at 50yds.
I just spun the dial down about 20 clicks and kept on hunting, three straight head shots at distances from 25-100 yds confirmed it enough for me.
the brake changed how the rifle sounded too, it was pretty cool to miss and see the rabbit look around like what was that?
they'd then resume eating until I shot at the bottom of their head then flap they went over, and tried running for a bit.
Ian
Notorious member
Still using this exact load from post #55 except I'm going on 2nd firing of some brass and I made the expander a little bit smaller:
Brass is Federal factory new 300BLK bulk, all test loads were with virgin brass. I did a VLD inside deburr after resizing and left the rest alone. The length of the new stuff is very consistent.
Primers are TulAmmo AR small rifle.
Expanded with home-made expander/bellmouth tool to .309" ID
ACE 235 grain PLAIN BASE BLK bullet cast from air-cooled 2COWW, 1 pure, 1 SOWW that I cast five days ago, sized in a .309" push-through and lubed in a .310" H&I die, bottom two grooves only. Bullets come out about .3098". I either need to size larger or expand less, the neck tension is a bit light on these.
Seated to crimp in the groove, I'll have to measure COAL and unfired brass. They are about as long as will crimp in the forward groove and as long as will possibly work in a Gen 2 Pmag.
Crimped firmly in a Lee Precision FCD to tuck the OD of the mouth flush in the groove behind the first driving band.
Next test will involve some stacks of old catalogs from work. These bullets are still soft, haven't tested them since a week after they were cast but I expect around 12 bhn tops. Based on how the size of the entrance holes they made in empty steel refrigerant kegs I'd say there is no need for a subsonic hollow point design at all.
Brass is Federal factory new 300BLK bulk, all test loads were with virgin brass. I did a VLD inside deburr after resizing and left the rest alone. The length of the new stuff is very consistent.
Primers are TulAmmo AR small rifle.
Expanded with home-made expander/bellmouth tool to .309" ID
ACE 235 grain PLAIN BASE BLK bullet cast from air-cooled 2COWW, 1 pure, 1 SOWW that I cast five days ago, sized in a .309" push-through and lubed in a .310" H&I die, bottom two grooves only. Bullets come out about .3098". I either need to size larger or expand less, the neck tension is a bit light on these.
Seated to crimp in the groove, I'll have to measure COAL and unfired brass. They are about as long as will crimp in the forward groove and as long as will possibly work in a Gen 2 Pmag.
Crimped firmly in a Lee Precision FCD to tuck the OD of the mouth flush in the groove behind the first driving band.
Next test will involve some stacks of old catalogs from work. These bullets are still soft, haven't tested them since a week after they were cast but I expect around 12 bhn tops. Based on how the size of the entrance holes they made in empty steel refrigerant kegs I'd say there is no need for a subsonic hollow point design at all.
Ian and Josh, how different is the ACE bullet from this PB?
http://noebulletmolds.com/smf/index.php/topic,1067.0.html
http://noebulletmolds.com/smf/index.php/topic,1067.0.html
I'm not Josh or Ian, but they appear identical
http://castboolits.gunloads.com/showthread.php?234526-A-C-E-300-BLK-subsonic-boolit
http://castboolits.gunloads.com/showthread.php?234526-A-C-E-300-BLK-subsonic-boolit
I've not ventured into the realm of subs, so no experience there. You could try http://www.300blktalk.com/forum/viewforum.php?f=185&sid=92b3b8de0434fbf7cca6a93881d2c70d
or wander around over at castrated boolits