300 aac blackout
- Thread starter captainmike
- Start date
I just picked up a LEE 300BLK factory crimp die from WSS for $18. Figured I'd give it a try and see if it changed anything. I've always been a little worried loading the bullets that don't have a caneleur, if they hit the feed ramp and push in that changes pressures drastically. This should give me some piece of mind.
I've never used a case guage, I measure for length after forming and trimming but I just drop the empty case into the chamber and if the bolt will close on it easily i think it's good.
I got lucky. I ordered a set of Lee 300BLK dies from Brownells for $27. The description said it was a 2 die set ie sizer and seater and the website doesn't show a 3 die kit with the crimper. Got my package and go figure, it's the 3 die kit. Contacted Brownells and they said that all's good. Got to like that.
On another note, while I was making up some 300BLK rounds tonight, I grabbed a handful of the cases I made up to check the headspace and they all dropped into the barrel, some just fit but I did notice that the case hangs out a hair by the base. I found that a bit weird, possibly a headspace issue? I'll try and take pics later. After I made up my ammo, I tried dropping them into the barrel but they would not sit all the way in. Turns out the bullets are hitting the lands and preventing the case from fully seating. WTF?
You can see the markings from the lands on the lower bullet just ahead of the case in the pic. No leade? Is this normal or is my barrel defective?
I've made up ammo using 155gr AMAX, 155gr SMK and 168gr SMK, all three hit the lands.
Here's an empty case, trimmed to 1.358". Notice it is sitting a bit proud. Sorry, crappy iphone pics.
This is where the ammo sits when dropped into the chamber.
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that ring is not from the lands........that is from your seating stem in your bullet seating die. Notice how it is far less then .300 in diameter...if that was your lands then your bullet would never fit in the bore period.
I am going to take a guess that your neck diameter of a loaded round may be to large for your chamber, this could cause some over pressure issues if it was the case. Measure the diameter of the neck of a loaded round.
I am going to take a guess that your neck diameter of a loaded round may be to large for your chamber, this could cause some over pressure issues if it was the case. Measure the diameter of the neck of a loaded round.
I got lucky. I ordered a set of Lee 300BLK dies from Brownells for $27. The description said it was a 2 die set ie sizer and seater and the website doesn't show a 3 die kit with the crimper. Got my package and go figure, it's the 3 die kit. Contacted Brownells and they said that all's good. Got to like that.
On another note, while I was making up some 300BLK rounds tonight, I grabbed a handful of the cases I made up to check the headspace and they all dropped into the barrel, some just fit but I did notice that the case hangs out a hair by the base. I found that a bit weird, possibly a headspace issue? I'll try and take pics later. After I made up my ammo, I tried dropping them into the barrel but they would not sit all the way in. Turns out the bullets are hitting the lands and preventing the case from fully seating. WTF?
You can see the markings from the lands on the lower bullet just ahead of the case in the pic. No leade? Is this normal or is my barrel defective?
I've made up ammo using 155gr AMAX, 155gr SMK and 168gr SMK, all three hit the lands.
It looks like you are seating your bullets a bit long. Notice how the mag rib hits the bullet and pushes it in pigeon toed? Also note how those bullets in the pic have a very long bearing surface and a fairly short nose. Seat your bullets a bit deeper and you will be fine.
The 300 BLK throat is designed for high pressure 110 - 130gr supersonic bullets.
FWIW Headspace has zero to do with the bullet. Headspace is 100% concerned with the case itself.
I did read somewhere about making brass in a progressive press where the shoulder would not get formed back far enough, so there could be a headspace problem, but only because your brass forming needs finessing.
the neck on the top loaded round in your picture looks longer then the one bellow it.......if they are all trimmed to 1.358 then your shoulders must be anywhere and everywhere but where they should be
the neck on the top loaded round in your picture looks longer then the one bellow it.......if they are all trimmed to 1.358 then your shoulders must be anywhere and everywhere but where they should be
Thanks, I'm aware that headspace relates to the case only and not cartridge OAL. The headspace concern in the first pic wasn't clear, here's what I meant using an empty case sized to 1.358". I don't have any gauges currently for 300BLK to verify.
I found the Sierra load data sheet and they list 2.105" as the COAL for 155SMK so I seated couple rounds to that. The ammo drops in to the case length but does not fall out easily, I have to use a rod from the muzzle to tap the out. I used the marker test to see if they were hitting the lands. Sure enough they still are. Is it safe to seat even deeper?
Hornady list 2.220" for the 155 AMAX, those hit the lands too.
You're looking at the wrong markings, yes the small ones on the front are from the seating die. The scuffed ones closer to the neck of the case are from the lands.
Update: Turns out, I need to seat 155gr SMK down to 2.05" (or 1.465" to OGIVE) to be able to clear the lands.
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^^^This^^^ You have no way of measuring headspace to size it to 1.358" unless you are using a tool such as a hornady headspace measuring gauge like the link below
http://www.hornady.com/store/Headspace-Gauge-Kits/
By using this gauge you would be able to measure the exact headspace of a fired cartridge, then FL size your brass to this same measurement. If you do not have a clear indication of the headspace you are looking for I would suggest buying a generic box of 300blk shoot a couple rounds, save that brass and don't size it but use it as a reference for your sizing operations. Not that I want to sound like a spokesperson for Hornady, but you might also consider a OAL gauge to measure your bullet seating depth. Your sharpie method works albeit a little crude, however it is really nice to put accurate measurements down on a piece of paper so they can be recreated later with excellent accuracy. See the other link below;
http://www.hornady.com/store/Lock-N-Load-OAL-Gauge-Straight-1Each/
Good Luck!!
http://www.hornady.com/store/Headspace-Gauge-Kits/
By using this gauge you would be able to measure the exact headspace of a fired cartridge, then FL size your brass to this same measurement. If you do not have a clear indication of the headspace you are looking for I would suggest buying a generic box of 300blk shoot a couple rounds, save that brass and don't size it but use it as a reference for your sizing operations. Not that I want to sound like a spokesperson for Hornady, but you might also consider a OAL gauge to measure your bullet seating depth. Your sharpie method works albeit a little crude, however it is really nice to put accurate measurements down on a piece of paper so they can be recreated later with excellent accuracy. See the other link below;
http://www.hornady.com/store/Lock-N-Load-OAL-Gauge-Straight-1Each/
Good Luck!!
It is OK to load into the lands. Just be aware it may make ejecting a live round difficult should you need to. A lot of the OAL issue with 300 BLK is to get the things to feed properly from the magazine.
Thanks. I have the Hornady Headspace gauge. Using insert #350B, my measurement to shoulder is 1.06"-1.064". I know Hornady neck measurement from the gauge is not the same as SAAMI spec measurements due to the gauge not sitting properly at the shoulders and that the 350B insert isn't optimized for 300BLK since Hornady doesn't offer a 300BLK insert. I believe SAAMI measures from the 0.3512" mark on the shoulder.
Barnes Vor-Tx factory ammo from my research measures 1.062"
I also do have that Lock N Load OAL gauge but I don't have the 300BLK case for for it. Brownells doesn't carry 'em and I don't have a spent case as yet. Still waiting for my upper/lower to ship.
Thanks for the info Suputin. Good to know.
I do have the tap that I have used to make my own modified cases for, If you would like send me a PM and I could tap you one and mail it back. Or you can easily seach it out on Ebay I think the tap cost me about $8, the same as a modified case from Hornady. The link below is a good writeup about making your own.
http://www.mdshooters.com/showthread.php?t=38054
http://www.mdshooters.com/showthread.php?t=38054
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I get around the pigeon toed stacking,by seating the bullets deep enough so that the measurement at the bullet where it comes in contact with the rib in the mag measures .250". The same as a 223,because that's what most of the mags are designed for.The 223 stack straight and then move to the center of the mag as they get pushed forward. I've read where some guys are sanding the mag ribs on the Pmags down, to get longer OAL and keep the rounds stacked and feeding properly.(bullet specific mag)
My gen 3's measure a bit wider between the ribs than the gen 2's . I heard Magpul had made the Gen 3's more BLK friendly maybe this was some of that.
That pic of my rounds in the mag was a gen3 20/5 Pmag.
Ok, some folks under the impression that my cases are out of spec despite all the measurements I've posted. So to help clarify things, I documented the process of how I made up my 300BLK cases. Correct me if I missed or fracked up a step or process and if my cases are out of spec.
To be honest, I hope I did miss a step or screwed up along the way during the process and my formed brass is junk so I don't have to deal with warranty issues etc. I'm humble enough to admit my mistakes and take blame for fracking up in order to learn and be safe. I'm not exactly new to reloading and have done my share of pistol and bottle neck reloading without any issues. I am, however, new to 300BLK and forming my own cases.
Step 1: Brass used were originally sized with a RCBS small base 223 die so I replicated that for this particular case which was not resized since it was tumbled.
Step 2: Cut brass to rough size.
Step 3: Deburr and chamfer.
Step 4: Lube case and size with 300BLK FL sizing die. Turn case 90 degrees and resize.
Step 5: Trim to 1.358" according to Hornady reloading manual 9th ed.
Step 6: Deburr and chamfer again. Don't need another pic.
Step 7: Measure case to verify trimmed size is 1.358"
Step 8: Measure neck diameter to ensure it is within SAAMI specs of 0.334"
Step 9: Measure base of case to ensure it is within SAAMI specs of 0.3759"
Step 10: Measure headspace to ensure it is withing SAAMI specs of 1.0707" from diameter 0.3512" at the neck. Hornady gauge being 0.350 (350B insert) I deducted 0.0012" from 1.0707" for 1.0695"
Step 12: If all above measurements are within SAAMI specs, verify the case will chamber.
To be honest, I hope I did miss a step or screwed up along the way during the process and my formed brass is junk so I don't have to deal with warranty issues etc. I'm humble enough to admit my mistakes and take blame for fracking up in order to learn and be safe. I'm not exactly new to reloading and have done my share of pistol and bottle neck reloading without any issues. I am, however, new to 300BLK and forming my own cases.
Step 1: Brass used were originally sized with a RCBS small base 223 die so I replicated that for this particular case which was not resized since it was tumbled.
Step 2: Cut brass to rough size.
Step 3: Deburr and chamfer.
Step 4: Lube case and size with 300BLK FL sizing die. Turn case 90 degrees and resize.
Step 5: Trim to 1.358" according to Hornady reloading manual 9th ed.
Step 6: Deburr and chamfer again. Don't need another pic.
Step 7: Measure case to verify trimmed size is 1.358"
Step 8: Measure neck diameter to ensure it is within SAAMI specs of 0.334"
Step 9: Measure base of case to ensure it is within SAAMI specs of 0.3759"
Step 10: Measure headspace to ensure it is withing SAAMI specs of 1.0707" from diameter 0.3512" at the neck. Hornady gauge being 0.350 (350B insert) I deducted 0.0012" from 1.0707" for 1.0695"
Step 12: If all above measurements are within SAAMI specs, verify the case will chamber.
Got a source? Sounds like a great idea! Thanks.
looks okay now that I look at it closer, the space your looking at is all part of the bevel of the chamber mouth so the rounds get steered into the chamber.......I missed the bevel last time and like you thought the brass was sticking out to far......there is a crude way to check this and I will PM you the details
Much appreciated!
I took the bolt off my other AR and check to see if the bolt would close and lock up which it does and extracts the brass without any problems.
