300 AAC confusion

[Not a Clue]

Hello all, new reloader here and I'm a bit confused and could use some insight on a problem I'm running into and can't find an answer to.

I have Hornady 155 Gr ELD Match (it's all I could find in stock locally), and I started with CFE BLK. However, there's a discrepancy between Hodgdon and Hornady's information and I'm stuck.

Hodgdon doesn't list 155 gr, only 150, but Hornady lumps 150-155 Gr in the same load sheet so I assume if I'm using Hodgdon's data for 150 gr, it should be very close.

Hodgdon is specifying a starting load of 18.8 Gr, going up to 20.5C and they are showing an COAL of 2.235".

Hornady doesn't list CFE BLK in their book, nor in a call to them, do they offer any advice. Their book shows using the 155 Gr. ELD Match bullets, the COAL should be 2.110".

That's a heck of a difference, 1/8" to be exact. Plus 20 gr in that 300 cartridge is close to full. I went to a local gun store that has a pretty smart reloading guy in there and he raised his eyebrows at it and said he didn't understand the vast difference either.

My concern is which COAL do I use? I've measured my chamber and I'm pretty confident that a 2.235" COAL is going to be far into the lands. Do I load with 18.8 gr, and use the Hornady COAL of 2.110"? If I do, surely that 18.8 gr is going to be compressed, which I assume is okay?

I called Hornady and didn't get much help, and emailed Hodgdon but hadn't heard back and I'm just trying to understand how to proceed forward from here.

Supersonic load, obviously.

Go easy on me, I'm a newbie

 

[FLIGHT762]

My concern is which COAL do I use? I've measured my chamber and I'm pretty confident that a 2.235" COAL is going to be far into the lands.

^^^^ This will be your answer. ^^^^ When you get the bullets, measure when they hit the lands, back off of them and go from there. Start at the starting load and work up.

 

[Deleted member 113831]

The part of the ogive that measures .250" has to sit behind the front guide rib on a 223 mag.

In my Pmags this means I use a 25 caliber comparator insert (.250" hole), and seat CBTO length of no more than 1.670".

A dedicated 300blk mag will give more latitude.

 

[Not a Clue]

So if I use the measurements from my lands, allowing a little space to jump, I'm closer to 2.120" with the bullets I'm using.

That brings me back to one of my original questions. At 2.120" COAL, 19 gr is about at the neck so that means I'm going to have to compress it about 1/8" to get the bullet to that seating depth. Is that okay? Normal? Everything I have loaded prior to this was more in the 14-15 gr range so there was plenty of space. With this powder, it's almost to the neck, and heading towards the max load, I think it would be up in the neck, meaning it would be one heck of a compression to make that work with the COAL I need.

I hope I'm describing it all correctly. Forgive me if I'm not clear.

 

[Deleted member 113831]

So if I use the measurements from my lands, allowing a little space to jump, I'm closer to 2.120" with the bullets I'm using.

That brings me back to one of my original questions. At 2.120" COAL, 19 gr is about at the neck so that means I'm going to have to compress it about 1/8" to get the bullet to that seating depth. Is that okay? Normal? Everything I have loaded prior to this was more in the 14-15 gr range so there was plenty of space. With this powder, it's almost to the neck, and heading towards the max load, I think it would be up in the neck, meaning it would be one heck of a compression to make that work with the COAL I need.

I hope I'm describing it all correctly. Forgive me if I'm not clear.

As a general rule, compressing powder is not a good thing.

 

[Not a Clue]

As a general rule, compressing powder is not a good thing.

That’s what has me pausing and asking these questions. It doesn’t “feel” right in my mind and being new to it, I’d prefer to avoid doing really stupid things.

 

[NighthawkCG]

Bolt or semi? It can make a difference on feeding and/or mags...


Then...

I would compare known, published bullet lengths (and weight) to the eld-m bullets you have and then try to work a comparable bullet seat depth (in the case).

(case length + bullet length) - COAL = Depth of bullet in case

This speaks to your case volume and how much you are (or aren't) compressing your load. Some powders do ok with compression, some not so much. Either way, if you start on the lower side of the listed range, and at a bullet seating depth (NOT COAL or CBTO) the same as a known safe load, you should, theoretically, be ok. There will be slight differences in pressures due to bearing length etc, but it won't be from compressing the powder. You can then work up and down to find the combinations that works for you.

This may take time and resources to figure out, but it is one way to figure it out safely for your rifle.

JBM - Bullet Length List

www.jbmballistics.com

ELD-M = 1.195"
HDY IB (150) = 1.260"

(1.363+1.260) - 2.235 = .388" depth in case for inter bond

Now switch it around for the ELD:

(1.363+1.195) - .388 = 2.17 COAL

The ELD seated to 2.17 is similar to the HDY IB at 2.235 when talking about case capacity/fill/compression. There are slight differences in volume with different shape boat tails, etc, but for the most part, it is pretty darn close.

Hence, I would start around that OAL, at minimum load and work up.

 

[Not a Clue]

Semi. Thanks for the info. I’ll try to take some measurements and photos and post them tomorrow, then you’ll see what I’m seeing.

 

[hlee]

Bear in mind that Hodgdon does not list the eldm bullet for the 300 black out. They list the interbond. This may well be a stubbier bullet, and be able to seat at the designated coal without compressing the listed load. If it were me, I would move to a powder listed by a Hornady, or a bullet listed by hodgdon...

 

[rjacobs]

The 150g Hornady IB that Hodgdon references is 1.260 in length.

The 155g Hornady ELDM is 1.195...

So just that difference would make your COAL 2.17 if seated to the same point.

You are wanting to go another .05 under that which obviously will add pressure, but likely not to much.

I would back off AT LEAST a full grain from Hodgdons starting number and start from there. Shoot a pressure ladder in like .2 or .3g increments, 2 rounds per should be plenty. I wouldnt run up to their max book value, but if you started at say 17.5g, I would load to probably 19 or 19.5g...

Thats just me. I like to find pressure limits IN MY GUN before I work on any other part of a load.

When I first started loading 300blk, 2012 time frame and there wasnt A LOT of published data, most was recipes from other reloaders. I started loading 150g FMJBT pulls with H110. I got BAD pressure signs at least a full grain if not 1.5g BELOW the published book max. So had I started closer to book max, I would have had a bad day.

 

[roggom]

Just wondering how far you intend to shoot? The 300 Blk is a close quarter round and Im sure it has a bit of reach. Just that there are plenty of 125 and 110 loads out there without having to compress so much and or crimp. Also Hornady SST/FMJ and Nosler BT are pretty inexpensive. makes for a fun day at the range and less failure to ejects/feed. Either way good luck with the load.

 

[rjacobs]

Just wondering how far you intend to shoot? The 300 Blk is a close quarter round and Im sure it has a bit of reach. Just that there are plenty of 125 and 110 loads out there without having to compress so much and or crimp. Also Hornady SST/FMJ and Nosler BT are pretty inexpensive. makes for a fun day at the range and less failure to ejects/feed. Either way good luck with the load.

I think you missed the part in the OP where the bullet he has is all he could find so he is working with what he's got. I cant blame him. I agree with you its an odd bullet(the 150g in general outside of cheap 150g FMJ pulls). I stick to 110g or go all the way up to 190-225's for subsonics.

 

[jomiba]

Does 2.235 fit in your mag? If it does i would think it would chamber and stay off the lands. If it doesnt fit in the mag load a dummy round to mag length and measure. You may be able to make the coal long enough to not have to compress the charge.

 

[rjacobs]

2.260 "in theory" fits in an AR15 mag...

But as @Skookum points out, you are limited by the bullet on the mag rib, unless you run a 300blk modified mag. Thats why on MOST 300blk loads the COAL is well short of 2.260.

 

[Not a Clue]

I'll have to let you know the answers to those questions. I forgot to bring it today so I can't measure anything today. I'll make sure I bring it tomorrow so I run the checks.

 

[roggom]

No, I dig it. Use what you have. That is the beauty of the 300blk, it is the garbage disposal of cartridges. Use up all of those spare flat based hunting bullets, form old 223 brass, and does not take a lot of powder. I actually traded a bunch of 155 scenars for some SST and other lightweights when I got my upper.

BTW midway has Hornady 125 FMJ 100/$23

 

[Not a Clue]

Sorry it took so long to get back to you all. I needed to time to document it correctly to get the proper help.

Here's where I'm at, and what I'm confused by.

Took the OAL gauge and inserted a bullet, pushed it back a good amount and snugged up the thumb screw so I could insert it into the clean chamber.

Insert it into the chamber and loosen the thumb screw and then gently push the gray rod until it stops, with light tension. Tighten the thumb screw and remove it all. The bullet comes out still in the cartridge so I know it's not jammed into the lands.

The problem I get is that this OAL is really short by all documented standards. It's so short that the Hornady gauge still has some of the gray protruding that keeps me from measuring it accurately (see photo). See the small part of the gray rod that's sticking past the casing?

I manage to get it measured and it's showing :

The Hornady book shows the OAL using this bullet to be 2.110". That would put me at .020" into the lands (roughly) with the factory length.

Here's the case with 18.9 grains of CFE BLK (amount comes from Hodgdon's site). You can see it's up to the neck.

However, here's how deep the bullet shows it should be seated, to be touching the lands, with zero jump.

Here's how much room I have (roughly) from the powder to the top of the case

That means I'll have to press it into the powder about .250". Doesn't seem right to me. I thought I wanted some level of jump, but even the Hornady book OAL has me into the lands +.02".

I have a couple 300 Blackouts so I checked the depth on all of them and they are all right in that same area, so it doesn't appear to be anything unique to this chamber.

I'll note again, I'm BRAND new to reloading, I've loaded this cartridge with another powder a few times for some testing (and shot, chronographed them), so my knowledge is limited. My gut tells me this isn't right and I need to stop, which is what I did. However, I'm trying to understand what's wrong here, or what needs to be changed, or what I'm doing or measuring incorrectly because it doesn't seem to add up to me.

This is on a semi-auto. I assume I want some jump in there, correct? Should I just skip this powder, go back to one that calls for less powder and then set the bullets back so I have a .050" or so jump and work from there? Or am I completely misunderstanding everything that I'm reading, and I need to go back to the beginning and learn it again, paying more attention this time around?

I appreciate your time and advice, in advance!

 

[Dead Eye Dick]

Might also want to invest in a couple more reloading manuals. While the specific bullet probably won’t be listed, the powder charges for similar bullets should be “similar” as well. Not all listed data is perfect. Found out the hard way.

 

[Deleted member 113831]

Problem #1- Where did this barrel come from, and how old is it?
Back before the 300 Blk was a SAAMI cartridge, it's parent the 300 Whisper had a shorter throat. That can be solved with a reamer if that is the case.

Problem #2 - I have had a suspicion for a while that some data in reloading manuals is generated by something like Quickload, and not by a human being. I have seen some fairly absurd loads in manuals for 300 winmag for instance. The book lists more powder than will fit in the case!!

Use your common sense, if the bullet won't fit, then it won't fit. Adjust the charge to represent 100% load density, as long as it is within pressure limits, and shoot it. If it shoots with 16 grains...or whatever it turns out to be...then rock on. If not, try another powder.

Just because "it is written" doesn't make it gospel in this case.

 

[Not a Clue]

All 3 blackouts I have are less than a year old and all of them measure the same.

That load data seems to be consistent on the Sierra load data and the Hodgdon site, along with the Lyman, I think. I’m not sure it was Lyman but I had a guy at the place I got the powder look and he pulled out 2-3 books and all of them said the same thing.

Should the Hornady load length set the bullet in the lands? Because it does. The 2-3 other books showed an even longer length, putting those even further into the lands.

 

[Flightmurse]

So to be clear, you are loading supers in an ar platform? You need to be very careful loading for this round. It is not unsafe, but this is a rough one to learn on because there is a lot of experimenting that goes on that take some experience driven intuition.

When I was shooting blackouts in a semi I stuck with 125gr Speer tnt’s for my supers with h110, or 220 grain lrn with imr 4227. Now I use a single shot and use everything from 90 grains to 220 depending on what I’m in the mood for.

 

[Deleted member 113831]

How about you load to whatever length works in your gun, and start with a minimum charge and work up?

I know it's crazy, but just might work.

 

[Not a Clue]

How about you load to whatever length works in your gun, and start with a minimum charge and work up?

I know it's crazy, but just might work.

That’s what I’m trying to do. The questions I asked, with photos above show the length it needs to be to hit the lands and the full cartridge in the photo is a minimum load, according to no less than 3 loading sources. I have no problem abandoning this powder, I’m asking because I’m trying to learn. While trying to learn, and following guidelines by the manufacturers, I’ve run into question that I don’t understand, which is why I stopped, and am asking questions.

Should my bullets be loaded to jump or be in the lands, because all load data I see, with this bullet, puts the load well into the lands?

My first loads were with H110, and they worked but were well into the lands at the 2.110” OAL. I was also getting a SD of 40, which is part of the issue I'm trying to resolve, which is why I'm asking the questions.

 

[Deleted member 113831]

That’s what I’m trying to do. The questions I asked, with photos above show the length it needs to be to hit the lands and the full cartridge in the photo is a minimum load, according to no less than 3 loading sources. I have no problem abandoning this powder, I’m asking because I’m trying to learn. While trying to learn, and following guidelines by the manufacturers, I’ve run into question that I don’t understand, which is why I stopped, and am asking questions.

Should my bullets be loaded to jump or be in the lands, because all load data I see, with this bullet, puts the load well into the lands?

My first loads were with H110, and they worked but were well into the lands at the 2.110” OAL. I was also getting a SD of 40, which is part of the issue I'm trying to resolve, which is why I'm asking the questions.

OK, I'll make it real simple.

Do not load into the lands...especially with a semi-auto. I don't care what length the book says.
If it is into the lands for your rifle...then it is wrong. (Or your rifle is wrong.)

Do not compress powder to the point you are crunching powder kernels. I don't care what the book says. If you are crunching powder kernels, you are wrong.

If the minimum charge requires you to crunch kernels...then the book is wrong.

Is any of this unclear?

 

[FLIGHT762]

Time to find another bullet. Looks like the ELDM profile isn't a bullet for the 300 Blk. I had a similar issue with a .358 Win. lever gun and a Nosler .358 200 & 225 Grain Accubond.

As dear old Dad would say "You're trying to put 10 #'s of shit into a 9# bag".

 

[Not a Clue]

OK, I'll make it real simple.

Do not load into the lands...especially with a semi-auto. I don't care what length the book says.
If it is into the lands for your rifle...then it is wrong. (Or your rifle is wrong.)

Do not compress powder to the point you are crunching powder kernels. I don't care what the book says. If you are crunching powder kernels, you are wrong.

If the minimum charge requires you to crunch kernels...then the book is wrong.

Is any of this unclear?

None of it's unclear. I posted it because I said I thought it wasn't right and was looking for confirmation that I wasn't overlooking something. I'm not debating that I should be doing it, I'm asking to help me understand that my thought process of NOT LOADING IT was correct. Sounds like it was.

Based on what I'm measuring, my OAL needs to shorten up quite a bit, regardless of the powder used. I'll go back to the H100, load them shorter, so they aren't in the lands, and give that a try.

I appreciate your advice, it confirms what I was pausing for. Hopefully getting it out of the lands will drop my SD down to reasonable levels. I'm not shooting matches, but would like to get the round to be a little better than I'm seeing now.

 

[Not a Clue]

Time to find another bullet. Looks like the ELDM profile isn't a bullet for the 300 Blk. I had a similar issue with a .358 Win. lever gun and a Nosler .358 200 & 225 Grain Accubond.

As dear old Dad would say "You're trying to put 10 #'s of shit into a 9# bag".

It's the only option I had at the time. Anyone got any recommendations for a different profile bullet? I'm not shooting matches with it, a FMJ would be fine.

 

[FLIGHT762]

Buy a bullet with a flat base and a more compact profile. You don't need boat tails in that cartridge. If you live anywhere near me, I'll give you some Speer 150 FBSP to try. If I was loading S/S for the 300 Blk, I would be using bullets in the 125 gr. range.

 

[Not a Clue]

Buy a bullet with a flat base and a more compact profile. You don't need boat tails in that cartridge. If you live anywhere near me, I'll give you some Speer 150 FBSP to try. If I was loading S/S for the 300 Blk, I would be using bullets in the 125 gr. range.

Thanks, I'll look into making that change. I was looking for 125's but unfortunately, not much is available these days. I'll keep my eyes open and my internet searches going.

 

[Deleted member 113831]

Thanks, I'll look into making that change. I was looking for 125's but unfortunately, not much is available these days. I'll keep my eyes open and my internet searches going.

I'm loading 150 grain Speer Flat noses in mine. (30-30 bullet)

The beauty of this cartridge is it's ability to eat just about any 30 caliber bullet.

Even though it is technically a bottle necked cartridge, it acts much more like a magnum pistol cartridge.

It is essentially a garbage disposal of a round...use whatever magnum pistol powder you have laying around, along with whatever left over 30 cal bullets and they will probably cycle and group inside a silhouette at 150 yards.

 

[Not a Clue]

Safe to use this bullet profile? This is the depth it would be at, toughing the lands. It's 150 grain and considerable shorter on the bullet length. This is what the guy sold me when I told him I was loading 300 blackout. I didn't realize they had the cannelure on them until I opened the box. Not knowing if that was acceptable, I went back and bought the ELD Match, as it was the only thing in stock. I assume it's safe to use these types of bullets, with the cannelure? Again, just starting so I'd rather ask the stupid questions now than make a bad mistake.

 

[Dead Eye Dick]

Very long, VLD bullets work great in a 300 Whisper single shot, best a TC Contender or a custom XP100. SD’s are an accuracy killer but for the purpose intended, (knocking down heavy steel targets at distance) they can do the job.

However, we have found tha 110’s and 125’s work great in bolt and AR style rifles. They are so trouble free, and have such nice ballistics, that unless, suppressed, subsonic loads are required, it is hard for members of ourfamily to consider much else. That would be my recommendation.

While purchasing locally is always preferred (gotta take care of those who take care of you). If they don’t have it, going online is an answer and a short check of at least one retailer shows at least some brands and types of 110’s and 125’s in stock.

 

[isofahunter]

As stated above poor choice of bullet profile for this cartridge. I run 170 Sierra GK for the 30 30 in a subsonic and it rocks. I have had best luck with flat base and flat faced bullets in Sub and lighter bullets for super 110- 130.
Midwayusa.com has bullets in stock that will work for you FYI.

 

[spife7980]

Safe to use this bullet profile? This is the depth it would be at, toughing the lands. It's 150 grain and considerable shorter on the bullet length. This is what the guy sold me when I told him I was loading 300 blackout. I didn't realize they had the cannelure on them until I opened the box. Not knowing if that was acceptable, I went back and bought the ELD Match, as it was the only thing in stock. I assume it's safe to use these types of bullets, with the cannelure? Again, just starting so I'd rather ask the stupid questions now than make a bad mistake.

View attachment 7429959

Cannelure is a non factor, it’s there if you want to seat deep and crimp a bunch like an old timer but you can completely ignore it also, I know I always have.

 

[Not a Clue]

I don't think I'm getting the right measurement to the lands. I'm stopping at the very least bit of resistance. If I push further, the bullet OAL is about 2.280" which is in line with what all the specifications would be for the Max COL. I feel like I'm stopping short of the actual place I should be stopping, which is causing me this confusion. Is that's where the lands are, at 2.280", then it means there's a pretty huge jump when I seat that bullet to the Hornady recommendation of 2.110". One of the books the guy looked it up in (maybe a green book, Sierra or RCBS?) showed a COAL of 2.180". That would make more sense to me. That would be .100" jump instead of a .170" jump.

One point that I notice, if I set the gauge with the bullet in it at 2.180" and put it in the chamber, every time I pull it out, the bullet is still in the cartridge. If I put it to 2.280", every time I pull it, the bullet is in the barrel. To me, that's telling me that I haven't been getting the right measurement all along, I've been stopping way too soon.

That makes more sense, doesn't it?

 

[spife7980]

Color it with a sharpie, see if your short measurement gives you imprints from the lands. Your long one will have imprints.

You can shorten a loaded round incrementally with the seating die and find the point where it stops putting the imprints in the bullet.

 

[Not a Clue]

Color it with a sharpie, see if your short measurement gives you imprints from the lands. Your long one will have imprints.

You can shorten a loaded round incrementally with the seating die and find the point where it stops putting the imprints in the bullet.

Did exactly that. At 2.110", I see no marks on the sharpie. 2.180", no marks. 2.280", I see marks. What I believe was happening is that I wasn't holding the back end of the gauge perfectly in line with the bore. If I wiggle that around slightly, it seems to allow it to go up to the place where it's more of a hard stop. I trust that's the place I'm looking for, correct? Not having ever felt what it's supposed to feel like, I stopped at the first sign of resistance. A little push further and it really stops.

 

[spife7980]

I never use the tool myself but that’s my understanding of how it’s supposed to work. Looks like you’re figuring it out now

 

[Doom]

Op,

If you look at the Hodgdon data closely, you will see that CFE BLK is not a powder that fits a 150 gr bullet. With a long bullet seating and a compressed charge the load develops only 33,500 psi. It is too slow and bulky to get good performance. The long COAL is to maximize case capacity. If you read the powder description its optimized for heavy subsonic loads. Hence the high volume.

Botton line is your bullet, cartridge and powder don’t play well together.

 

[Not a Clue]

Op,

If you look at the Hodgdon data closely, you will see that CFE BLK is not a powder that fits a 150 gr bullet. With a long bullet seating and a compressed charge the load develops only 33,500 psi. It is too slow and bulky to get good performance. The long COAL is to maximize case capacity. If you read the powder description its optimized for heavy subsonic loads. Hence the high volume.

Botton line is your bullet, cartridge and powder don’t play well together.

I'm with you there. I have some H110 that I'll switch back over to and I'll use that, along with a different bullet once I get them, and hopefully this solves the issues. It's good to be able to talk through it with knowledgable people on this forum. That helps.

 

[spife7980]

Op,

If you look at the Hodgdon data closely, you will see that CFE BLK is not a powder that fits a 150 gr bullet. With a long bullet seating and a compressed charge the load develops only 33,500 psi. It is too slow and bulky to get good performance. The long COAL is to maximize case capacity. If you read the powder description its optimized for heavy subsonic loads. Hence the high volume.

Botton line is your bullet, cartridge and powder don’t play well together.

Bullshit. It works wonderfully with 150 gr bullets.

Also, youre just simply wrong.

For me 19.4 gr with a 150 gameking was a great performer. It was right around 1800 fps in my 16" barrel I think (sold the rifle awhile back)
20 grains was juuuust starting to give me some pressure signs.

 

[Doom]

Calm down. Didn’t say it wouldn’t work, The powder is slow and to get comparable velocity they set the bullet out long. Thats why the COAL seems long. No doubt it can shoot but it doesn’t mean its the optimum powder.

 

[Snuby642]

Quit trying to stuff eld bullets in it and get rnfb.

 

[Doc68]

I was using 4227 powder loading supers with the barnes black tip 110gr. The case was full to the case mouth and seriously compressed. Never had any issues. I did use a string to pull the trigger the first time.

 

[Not a Clue]

It looks to me, since my revelation about the length being wrong, the way I was measuring it, that with that powder (CFE BLK), the ELD's will work fine. The Sierra TMK's seem to be very similar and they are showing a OAL of 2.250". If I loaded them at 2.250", or slightly less, it looks like it will work fine and not compress the powder and work with that bullet. I'll use these until they are gone and then switch to something else.