Bullet embedment concern - new to 300 BLK loading, please help.

[hcb]

Hello, folks, I've been handloading rifle/pistol only for 2 months and I've got a concern here without enough experience to allay it. To just get this out there: my concern is how far the bullet seats into the case mouth. More precisely, my concern is how LITTLE it sits into the case mouth. My calculations show the bullet to be embedded (seating depth) only 0.110". That seems very shallow to me.

My first mistake maybe that I had read (and sort of believed) that almost any .308 bullet could be used in the 300 BLK ammunition.

I bought a box each of 100 of: Sierra #2120 (125 gr soft point) and Hornady #3035 (150 gr RN soft point). The Hornady looks like it's really more for the 30-30 carbine rounds. Regardless, the Sierra measures out to about 0.880" and the Hornady very close at about 0.905".

I followed published data from Nosler for 125 gr bullets (and also took measurements from a factory-load). I trimmed cases to 1.368" per the Nosler information (my factory Remington ammo cases measure 1.355". The target COAL is 2.260". After seating the bullet enough to make me feel comfortable it wasn't about to just fall out of the case, I measured my COAL and get 2.138". My math is: 0.880" + 1.368" = 2.248". 2.248" - 2.138" = 0.110". The Sierra bullets do not have a cannelure to crimp in to. The Hornady bullets do, but it's so far up the bullet that my COAL would be about 1.881" (calculated on dimensions). My .223 Rem handloads targeted the same COAL of 2.260" for the 300 BLK, as I recall.

As I stated, I'm new to this so I don't have enough experience to know for sure, but 0.110" seems too shallow. I am concerned about: even minor mishandling of the rounds could dislodge the bullet, even minor mishandling of the rounds could seat the bullet deeper in the case, and finally, that the violent action of the AR platform I'll be using it in may cause the bullets to migrate farther into or out of the case. It's my understanding (from what I've read) that the amount of space/distance between where the bullet starts from to where it engages the rifling can impact chamber pressures. I won't rattle on any more than that. Those are my concerns.

I would very much appreciate any advice and information about this, please.

Thank you.

*edit* After posting this I had a thought; try putting it in the magazine. The bullet hit the ribs which normally guide the case mouth of the .223 Rem. I started seating the bullet deeper until it finally didn't hit the guide rib in the magazine. COAL was 1.948". That's quite a bit shorter than the COAL target of 2.260".
*edit*

--HC

[Sig220]

Read and use the search feature to find discussions that cover your dilemma.

Just know this......if you are not a experienced reloader, stick to published "recipes" to protect you and those around you.

The "recipes" will tell you the projectile, powder, charge weight and the OAL length....and additional data.

Random changes to recipes will result in a disaster if you are not lucky.

If everything is the same, shortening your OAL will increase pressure....sometimes to the point you will not be happy.

Nosler's load data published online lists load "recipes'' for the 125gn Accubond and Ballistic Tip. They don't list a load for Sierra projectile.

edited to add:

If you have proper case neck tension, you should not see any cartridge OAL length change using a AR. You can take a loaded round and push it nose first against your loading bench (wood) by hand and if it stays put........it will stay put in your AR. If you don't have proper case neck tension, you can adjust your die or in some cases have to reduce the diameter of your expansion ball. Some loaders swear by a crimp die and others swear at them!

I will not load a round where the projectile is not at least as deep as its diameter, which in our case is .30

I don't mean to come across too "curt", but reloading is a hobby with severe consequences if we are not careful.

[Aggie]

Are you maybe confusing the load specific COAL with the SAAMI spec? My hornady 9th edition book shows the #3035 at COL 2.220". Max as far as SAAMI specs goes is 2.260"
As far as 125's go hornady shows 2.100" for theirs and Nosler shows 2.060", I dont have any sierra info.

I've never shot reloads out of my AR but I've read a lot about the rib in the magazine causing feeding issues with some shapes of bullets but the people tend to cut the rib out so it feeds correctly (or try a different brand mag), seating deeper would not be the best choice especially as this changes your pressures and so the powder measurements from the book may not be safe for the shorter depth.

I've shot anywhere from 90 to 220gr bullets out of my handi and bolt actions but the amount of bullet in the case especially for the smaller bullets gets a bit low but I don't have to worry about the action.

Have you tried the hodgdon reloading site? You can select your powder and weight of bullet, for me the site is close but usually has slight changes to powder charge or length.

[here2day]

Sierra 300 BLK load data can be found via the link at the bottom of the press release at http://www.sierrabullets.com/resources/ ... -Gas-Tube/

[smustian]

STOP using those bullets in an AR platform. They are for 30-30 or bolt guns. As Sig said, stay with published data and bullets. You will find that 300 Blk bullets have a longer nose profile than carbine bullets. Trim your cases back to 1.358-1.360. If you do not have one, get a Lee Factory Crimp die and use it instead of the crimp on a seater die. I like a light crimp on mine but some people use nothing more than to straighten out the case mouth flare.

Sounds like you are using Magpul mags. If so, you can sand, trim, grind, etc the rib some so that they will not touch the bullet. I ground the ribs on mine down as far as the Dremel sanding bit would reach and have never had a problem. If the bullet nose is pushed over by the rib it can cause feeding issues.

I commend you for asking your questions before you or your weapon got hurt. We are always glad to help new reloaders out. It is always better to ask than to blow something up.

Welcome to the board.

[certifiable]

I load the Sierra #2120 125gr. Spitzer to 2.050" oal, 1.560" CBTO which seats the bullet 0.198" into the case neck using a trim length of 1.358", give it a very light crimp with the Lee FCD and have experienced no bullet movement within the case during cycling in the ar platform. By comparison, I load the VMax so that there is only 0.165" of the bullet seated within the case neck and have experienced no issues with that load either.

To get to the point, you cannot seat the 125gr spitzer to mag length

[rebel]

What powder are you using? I seat the 125 prohunter ( 2120 ) ar around 2.05 with an appropriate charge of w296. They are very accurate bullets. Forget about a cannelure, it does not apply here. As smus said, the Lee Factory Crimp die will hold you bullet in place without deforming it like a roll crimp. Just keep it light. Some use no crimp and neck tension suffices. Try both to see which one shoots the best.

[hcb]

Read and use the search feature to find discussions that cover your dilemma.
Just know this......if you are not a experienced reloader, stick to published "recipes" to protect you and those around you.
The "recipes" will tell you the projectile, powder, charge weight and the OAL length....and additional data.
Random changes to recipes will result in a disaster if you are not lucky.
If everything is the same, shortening your OAL will increase pressure....sometimes to the point you will not be happy.
Nosler's load data published online lists load "recipes'' for the 125gn Accubond and Ballistic Tip. They don't list a load for Sierra projectile.
edited to add:
If you have proper case neck tension, you should not see any cartridge OAL length change using a AR. You can take a loaded round and push it nose first against your loading bench (wood) by hand and if it stays put........it will stay put in your AR. If you don't have proper case neck tension, you can adjust your die or in some cases have to reduce the diameter of your expansion ball. Some loaders swear by a crimp die and others swear at them!
I will not load a round where the projectile is not at least as deep as its diameter, which in our case is .30
I don't mean to come across too "curt", but reloading is a hobby with severe consequences if we are not careful.

First, thanks for your reply and time. I did try a search but wasn't able to form the correct search string to find what I was concerned about precisely. I'm not saying it's not here, just saying my search got me a bunch of discussions from which is the best brass to convert to random posts with phrases such as "...in your case...".

I have no intention of trying to make my own recipe; I do have and use a physical manual and online resources like Nosler. The biggest stretch I make is the one I did here; using load data for the same weight bullet and type of bullet (copper jacket as opposed to cast lead). If that's stupid to do then I stand corrected. Otherwise, I stick to powder/primer/dimensional data and start at the lowest grains listed and often stay there. I have a chronograph to verify my load performance against specs.

I will seat another bullet in another case and try the push test. I have used the crimped cases on my .270 Win because the bullets I purchased had the cannelure. I didn't find the crimp to be terribly difficult; the instructions with the dies were straight forward and easy to follow.

You come across fine and I understand this "hobby" can be very dangerous or deadly. I've reloaded shotgun shells for 30 years and always followed recipes for those shells but also knew that shotgun shells are simple and rifle/pistol is not. I came into this with the attitude of trying to be safe doing something dangerous and showing it respect. That's why I'm here now; I see something that's seems wrong and I won't run with it unless I find solid reason to believe it's safe. To that end, I like you're rule of thumb of bullet diameter/depth and this isn't close.

Unless another reply answers all my questions I'm going to find published data/bullets to match my primers and powder and use different bullets on my cases to see what a proper handloaded shell should look like. Basically get some proper experience with the round.

Thanks again.

--HC

[hcb]

Are you maybe confusing the load specific COAL with the SAAMI spec? My hornady 9th edition book shows the #3035 at COL 2.220". Max as far as SAAMI specs goes is 2.260"
As far as 125's go hornady shows 2.100" for theirs and Nosler shows 2.060", I dont have any sierra info.

I've never shot reloads out of my AR but I've read a lot about the rib in the magazine causing feeding issues with some shapes of bullets but the people tend to cut the rib out so it feeds correctly (or try a different brand mag), seating deeper would not be the best choice especially as this changes your pressures and so the powder measurements from the book may not be safe for the shorter depth.

I've shot anywhere from 90 to 220gr bullets out of my handi and bolt actions but the amount of bullet in the case especially for the smaller bullets gets a bit low but I don't have to worry about the action.

Have you tried the hodgdon reloading site? You can select your powder and weight of bullet, for me the site is close but usually has slight changes to powder charge or length.

Thanks for the reply. What I'm seeing between replies here and having continued to look online for more information is that I went about solving this "problem" all wrong. I started at the end, not the beginning. Yes, the load data varies when it comes to COAL which I've learned now. The final answer is in the post after yours which links to Sierra's site with published data for the powder/primer/bullet combo I have showing a COAL of 2.000" which is about where I found my one reloaded shell would fit properly in the magazine.

I'm sorry. I'm and idiot and went at this backwards and also took the SAAMI spec as my target spec.

--HC

[hcb]

Sierra 300 BLK load data can be found via the link at the bottom of the press release at http://www.sierrabullets.com/resources/ ... -Gas-Tube/

Thank you for the reply. This is 1) the information I needed, 2) the way I should have gone about things from the start. My mistake. Lesson learned.

--HC