• Visit Brownells
  • Visit AR15 Builder
  • Visit
  • Visit Site
  • Visit Beachin Tactical
  • Visit Genesis CNC
  • Visit Ballistic Advantage
  • Visit Patriot Outfitters
  • Visit Cabelas
  • Announcements

    • Recent forum updates   08/21/2015

      Ladies and Gentlemen (and Tom), The forum has recently been migrated to new forum software. To those of you who have been here a while, please realize that it will take some time to get everything working. If you have just joined the site recently, we're very pleased to have you as well. Please be patient while the wrinkles get ironed out of the new system. Thanks!   Matt

300BLK reloading

60 posts in this topic

Posted

I got some time before I had to go to work today to cut,form & load some dummy test rounds for function testing.

I have about four or five .30 bullet types laying around , so I chose a Hornady 150 gr. sp & a Speer 130 gr. bullets.

I cut the top off the 5.56 brass with my Dremel tool with a reinforced cut off wheel & deburred cases before I formed them.

LH1688.jpg

They are a little long & will use my trimmer to trim them down to about 1.360" , to start out with . I will chamber them to see how they work . I will adj. as needed.

LH1689.jpg

The bullet on the left is the 150 Hornady & the right one is a 130 gr.,Speer Varmint bullet

( I shot a seven point buck in West Virginia with a M1 Garrand with this bullet & can tell ya ,it was devastating .)

LH1691.jpg

Share this post


Link to post
Share on other sites

Posted

I picked up some H110 & WW 296 yesterday for testing . I found a local reloading shop , go figure, & he had good prices on them .

I loaded some up with 2400 & can only get 16.5 grs. in the case with out compressing the charge . The H110 I got 20 grs. in there with room to spare .

I will testing the upper & ammo Friday & will post results & photo's.

Share this post


Link to post
Share on other sites

Posted

once you shoot some, try setting your resizing die to just touch the shoulder, you might gain a little more room for powder that way.

Share this post


Link to post
Share on other sites

Posted

All this brass was formed from cut down LC 5.56 brass. This case forming stuff is new to me .

Hay I'm a virgin again <laughs> !

Share this post


Link to post
Share on other sites

Posted

Got some Chronograph numbers today ,

125 gr. Speer , 16gr. ,2400        ,avg. 1954 fps.

150gr.sp. ,Hornady , 15 gr. 2400 , avg. 1723 fps.

125 gr. Speer , 19 gr. H110          ,avg. 2132 fps.

150 gr.sp. Hornady, 17 gr. H110,  avg. 1846 fps.

125 gr. ,Speer, 20 gr. , H110        avg. 2211 fps.

As far as grouping , I didn't do any ,because I am working up loads . I can tell you this ,the 20gr. of H110 looks good .

I did have a couple of primers that blew out part way with the 20 gr.load of H110. I used 7 1/2 Remington bench rest primers & I didn't like they way they seated or fit .

No primers showed any high pressure signs ( blow out primers can be caused by many things ). Kinda makes me wonder about the brass I was using.

I had several that fell out of the case when priming . This was once fired LC 5.56 brass, even though it was only a few ,its enough to change primer manufacturers, I will use CCI & WW  next.

Other than the couple of primers  (3) this is a awesome rifle to fire . I had a couple of people at the range ,that had never heard of the 300 BLK.

Can't wait to do some grouping.

Share this post


Link to post
Share on other sites

Posted

I got a call from my barrel mfg today. Told me that they had gotten a new blank and turned it. Only need to thread and chamber it. Told me it should go out the beginning of the week. If true, thats good news, but your numbers make it seem doubtful that I'll be able to make my desired  320 PF.  They did tell me that the 1/10 twist might help. but I can't imagine getting more than 100 fps out of my 18" barrel over your 16".  I was wondering, with your two hottest loads, was there any more room in the case for more powder? This may turn out to be a light, fun, hunting gun, but maybe not a major division comp gun. Regaardless, I'm still excited about building my first wildcat cal. AR.

Share this post


Link to post
Share on other sites

Posted

I think with H110 & WW296 , you could get two or more grains in there .

As said , There was no signs of high pressure on the brass that didn't pop the primer & ya know ,I've been thinking about that brass . Its range brass in some way I'm sure, might have been some ones last loading & they just happen to use Remington 7 1/2 primers (because they are the same color as factory primers )

I will make all future cases from known good once fired brass, but use this fodder until I see problems .

I'm not done with testing loads for this rifle &  she can be seen on the Rifles section ,under the 300blackout thread.  2300 fps can be reached with out a problem ,I think.

What fps. were you looking for again ?

Share this post


Link to post
Share on other sites

Posted

Try some commercial 223 brass, it should have thinner walls and hold a little more powder. CCI primers are generally regarded as the hardest and should give good service in a high pressure round like that. Watch your headspace too, that can cause the primers to back out.

Share this post


Link to post
Share on other sites

Posted

I'm still waiting for my HeadSpace gage set, ordered it almost three weeks ago from PTG .

This last loads we made up with Hornady brass ,.223 & I raised the charges to see how far I could go with this powder(s) cartridge & I found them .

I'm glad I only make five test rounds of each loading ,so as not to have to pull & recharge so many bullets .

20 grs of H110 or WW 296 with a 125 gr. bullet is what I concider max load in this rifle of mine .

18 grs. of H110 or WW296 for the 150 gr. bullets, would be a max loading .

My most accurate load so far ( really to early in testing to be sure ) was a 125 TNT , 20gr. WW 296 & a CCI primer , 2201  fps.

Now that I know what the max loadings are ,I can play with loads & primers to see what comes out on top & go with it .

I never intended this cartridge to be a tack driver , but more of a hunting rifle , but we will see once I get better optics on her .( and finish the POF lower that belongs on her )

Declaimer , these are my loads in my rifle & you should use caution & work up your loads in your configuration.

Share this post


Link to post
Share on other sites

Posted

I'm looking for 2300 with a 150gr or 1800-1850 with the 175 and 180gr to make 320 PF  (Power factor = bullet weight x velocity divided by 1000). Although I'm impatient about getting the upper put together, I'm prepared for the load development to be a slower ongoing effort for me. I still don't have the Foster dies and have no idea when they will get here. I'll be satasfied just to get the thing together and break in the barrel and start to see what kind of hits I can get at 200-300 yds with my friends ammo.

Share this post


Link to post
Share on other sites

Posted

The 1800 fps with the 175 might be done, but you are on your own there bro.

I've got enough blow out primers that's telling me I've went far enough & know the limitations of my set up.

I will probably not go that high weight of bullet unless I get a "can" for this rig. Which is why I'm looking at suppressor attachment muzzle devices .

Share this post


Link to post
Share on other sites

Posted

Got some Sierra 135 gr. MK's to load & made some test rounds for tomorrow .

case -ACC Remington 300BLK/primed

bullet -135gr. Sierra MK HPBT

powder - 17.2 gr. of H110

OAL - 2.096"

LH1763.jpg

Here next to my 125 TNT & 150 Hor. SP test rds.

LH1762.jpg

Share this post


Link to post
Share on other sites

Posted

I just made a deal with someone to get some 175 and 210 MK's to test out, in my quest for major PF. I don't have them in my hands yet but am planning to order some Vhita Vhouri N110 as I've heard some good things about it.

Share this post


Link to post
Share on other sites

Posted

Range session today & have some results from my loads .

This is the first rounds fired through this complete rifle with the POF lower & carbine buffer assembly, all new,never fired lower assembly.

The trigger sucks ,the rings are too low now & I guess I can't expect much precision work from a old Turkey scope .

125 gr. Speer TNT bullets , cut down & formed LC brass, 19 grs. of H110 ,

AVG. Vol. -2179 fps ,

good load, not bad groups.

150gr. SP , Hornady bullets, cut down formed ,LC  & Hornady brass, 16.6 grs. of H110.

AVG.VOL. -1900 fps,

not bad , had one blown primer ,but this brass has been abused in testing , all the rest of the brass looks good .

135 gr.,Sierra Match Kings, Remington , ACC 300 BLK brass, 17.2 grs. H110.

AVG.VOL. -1993 fps.

This bulllet is impressive , I will post a photo of the target of a 10 shot group .

This bullet shot about 4" high , I had to adj. the scope to get them into the dot of the target, after that I had no problem with keeping them there ,even with this scope & trigger.

After I shot the 10 shot group ,with the barrel hot after the shot string , I put four more rounds range to check Vol. & went from an avg. of 1977 to 2022 fps  for an average with hot bbl. , I was not expecting that , the ammo was all hand weighed & seated the same .

It was a 24 rd. test batch of the 135 gr. MK.bullet . Just some thing to think about .

Share this post


Link to post
Share on other sites

Posted

I chrono'd some of my first batch of 300BLK bullets today.  First of all, I post this for informational purposes only. This is my first involvement in loading rds where I'm not just copying someone else's proven load. I loaded 145 gr fmg bt bullets to 2.1 COL in brand new LC brass I cut to 1.36". I used 16.5 gr of Hogdon LIL'GUN powder. I found that my velocities varied widely. I used a borrowed Redding 3BR powder measure and measured the first 5 or 6 drops and then loaded my ammo with only one check in the middle. I'm not sure what to attribute the FPS variation to. I know that I got some bad readings with the borrowed chrono, so maybe my results are questionable. I got several readings with a low of 2020fps and a high of 2096 fps. I had some obviously false readings in the 3000's and some other readings in the 1600's. Don't really know what to make of it, but the majority of my readings were all in the 2000-2100 range so I'm guessing those are the good ones. I didn't see anything to indicate excessive pressure, but I have been told that the signs of over pressure can show up in as little as 1/2-1 gr increase in charge. I need to get 150 more fps using this bullet weight to achieve my desired goal. I'm thinking that I may need to load some heavier bullets. The only concern I have with that is that the heavier bullets may require large holdovers at longer range. I guess I have a lot of testing to do.

Share this post


Link to post
Share on other sites

Posted

How far was your Chrono from the muzzle ?

Muzzle blast can some times give false readings.

I have been lucky with my chrono , I had my first shot the other day show 950fps & I knew it was wrong . I changed the battery in the Chrono & all went well after that .

I would hand load your test rounds , not saying your powder measure is wrong ,but if it doesn't like the powder ,it could have metering problems . Some powders do that to them .

By hand weighing your charges , you can have better consistency & you can fine tune the charge better.Than once you have your load down pat , use the powder measure to copy it .

You can just add a few tenths of a grain at a time & see what happens .

I load three rounds each of progressively larger loadings & then if I get pressure signs I stop & pull the bullets of those over the charge weight of the one that started to show the high pressure signs & just recharge /reload those.

Share this post


Link to post
Share on other sites

Posted

Yeah, I think I need to take the powder measure out of the equation. Although it's a Redding 3BR match grade measure, which I thought was supposed to be one of the best. I also may have been a little close to the chrono. I was shooting without the handguard so I could adjust the gas system, so I had no sights on the gun and didn't want to accidently hit the borrowed chrono. I'm wondering how long I could load the next batch, I was thinking that if I could load them longer I might be able to safely get some more powder in the cases.

Share this post


Link to post
Share on other sites

Posted

I also use a Redding PM & its very good dispensing most powders , some powders don't work in just about any PM.

The COL of the round will be determaned by bullet configuration . You want it close to the rifling but not on top of it .

The lighter/shorter bullets , you don't have any thing stopping you with the COL , but getting into the heavies & there length will make it a problem .

Not only in the chamber ,but in the mag. .The longer heavy bullets will get interference with the rib in a std. mag. if set up with too long of COL.

You can make some dummy rds up with different COL & measure after test feeding into the chamber & if they don't have any marks from the lands , fail to feed or the bullet is pushed back farther into the case , you should be able to load a few test rounds to see how they work .

The 300BLK has a longer free bore to the rifling & that gives you a little lee way.

Are you using 5.56 cases or .223 ? The .223 will give you a hair more volume for powder.

You have to also remember that the bullet has to be supported in the case properly also . If its not , on a  auto feed type system can dislodge a bullet .

Share this post


Link to post
Share on other sites

Posted

I have .180" room from the front of my bullet to the front of the mag, so I don't think thats going to keep me from going a little longer, My biggest concern with these particular bullets is how much purchase the case has on the bullet. On my first batch I loaded to 2.1" col. With this setting the bullet cannalure is about .075" in from the case mouth. My friend that first suggested this powder told me that he has loaded up to 17.5 gr of this powder with no pressure problems, although when I ask what his fps readings were with that loading he tells me that he never chrono'd them? I'm think that as you suggest, I will load a small number of rd's with 17 an 17.5 grs, and that I will load the bullets + .075" longer. if I'm not close to my goal, I think it will be time to start trying those heavier bullets, and maybe order the other powder.

Share this post


Link to post
Share on other sites

Posted

Be careful , just because you can get an OAL close to the mag space allowed , different bullets may not chamber because of how they are made .

Make a dummy up to see if it will chamber with out pushing the bullet back or feed problems.

Besides ,if the OAL of dummy rd. works , you can aways use it to set up your seating die in the future.

Share this post


Link to post
Share on other sites

Posted

That sounds like good advice. I'm thinking that I'll make some dummy rds up to find out just how long I can safely go with this bullet weight/conf. Just wondering, I'f I load some dummys + .100" over my present  2.1" col and drop the bolt on them, and they are too long, What will happen is that the bolt will force the bullet back into the case untill the bolt is able to close,Correct? This will mean that, instead of headspaceing off the cartridge the dummy will haedspace off the point of interferance of the bullet, right? Won't that harm the barrel?

Another question, I have the 175 MKs now and see that they are very close to the conf of the 145's I have tested. Since I have no data to refer to, Is there any formula or rule of thumb to go by that would give me a starting powder charge if I used the same powder as before and loaded the 175's so that the base of the bullet is in the same place as when I was loading the 145's (same case capacity)?

Share this post


Link to post
Share on other sites

Posted

I am going to put some info on head space & COL (cartridge overall length)in a new thread in the reloading section for all to read , it may answer all your questions , maybe not specifically the 300BLK ,but at least you will know some thing more about it & come up with safer loads .

Share this post


Link to post
Share on other sites

Posted

Went to the range with a new Burris mount & some more 135 MK loads & have to say the Burris mount makes all the difference in the world .

The too low rings make sighting difficult to say the least.

I could only use the 50 yrd. range so I won't post ant targets ,but this load is pretty close to the one I want .

With a better trigger ,It will be a very good performer . I probably had a 1/2 " group at 50 yrds' & really wasn't trying very hard , I was using the chrono to test this load.

AVG. VOL. --2080

ES----------92

SD ---------30

The Extreme Spread , I'm going to have to work on, not sure why its up that high . could be a lot of things including how the Chrono is reading the bullet .

The Standard Deviation  is not bad , kinda makes the ES worthless.

This ammo was with Rem. ACC BLK primed brass, 17.5 gr. ,H110, 2.110 OAL.

Loaded on a Dillon 550B with Forster bench rest die set.

Share this post


Link to post
Share on other sites

Posted

survivalshop,

I picked up one of those Hornady COL gauges, and sent a couple of my fired 300 cases to them to drill and tap for me. Now that the guns done, I figure I'm going to see if my COL is limited by my chamber, the amount of purchase that the case has on the bullet, or the front of the Pmag. I've got an assortment of bullets ranging from 110 to 220. I've been told that I should try to see what results I can get with the 175's but I have some really nice Lapua 155's from one of my friends. I presently have enough powder to load maybe another 100rds. So I figure I'll try some more of the 145's upping the charge in 1/2 gr increments till I see signs of excess pressure. Along with that, I plan to load some of the 155's, 168's and 175's just to get a starting point for load development. Having never done this before, I'm a little bit confused about working on a load for power factor vs for accuracy. I assume that I can't really sight in with one of the bullet weights, check the chrono figures AND do the same for a different  bullet without having to resight in for the other weight bullet. Would that be correct?

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now