Loading for Hornady .224 75 gr BTHP Match in Match AR-15

[Blackcloud6]

I've been using Hornady .224 75 gr BTHP Match in my Highpower match rifle, an Armalite AR -15 for years. I didn't fire for a couple of years and came back just after scopes were allowed. So I had the upper converted to a rail upper for the scope and took off the A2 stock and put on a Magpul adjustable stock.

Now the bolt does not always lock to the rear on the last round. After much testing, I've determined it is the load causing the bolt to short-stroke. With US Military MILSPEC ammunition the rifle works fine consistently.

The load I have been using is 23.2 grains of IMR 4895. I was using LC brass but am now using Federal. So my question is: will increasing the load make the rifle work properly? How high can I go with IMR 4895? Hornady does not list IMR 4895 in their load data.

Will there be enough room in the case for increased powder?

Or should I switch to a different power? if so, which one?

 

[Charlie98]

Obviously something has changed with your rifle... I would work up your load again from scratch, using the factory load as a benchmark. There are other powders to use, it's true, but you are right back to working up a load from scratch.

 

[Blackcloud6]

Obviously something has changed with your rifle... I would work up your load again from scratch, using the factory load as a benchmark. There are other powders to use, it's true, but you are right back to working up a load from scratch.

Dennis, thanks. Yes, I figure I have to work up a new load, but what I need to know and can't find out is what is the high load for IMR 4895 for the Hornady 75 Gr ain HPBT bullet?

 

[Charlie98]

I don't have access to my loading books right now... does the Hornady book list H4895 with the 75's?

 

[2ndtimer]

According to Hodgdon’s website loading data, the starting load for a 69 gr Sierra matchking in .223 rem is 23.3 gr of IMR-4895, so you are definitely on the low end. They show a max charge of 24.8 gr, so you should be able to carefully work up to that level, or wherever you find best accuracy, reliability and your personal comfort level. Some believe that the .223 data is conservative for rifles chambered for 5.56 NATO and load even heavier. Check out other websites and published loading manuals from Nosler, Hornady, Sierra, Speer and Lyman and be careful.

 

[Blackcloud6]

I don't have access to my loading books right now... does the Hornady book list H4895 with the 75's?

The Hornady Reloading App does have H4895, The max for it is 23.3 gr. But H4895 and IMR 4895 are not the same.

This thread shows that one can go up to 24 gr with IMR-4895. https://www.thehighroad.org/index.php?threads/hornady-75-gr-bthp-223-loads.789677/

I can increase OAL a bit. I measured my current one to be 2.239. OAL for operation in a AR-15 magazine is 2.260 and the recommendation is to load for 2.250. I'll bring mine up to that and then work up loads and see which one consistently has the rifle operate consistently.

 

[Blackcloud6]

According to Hodgdon’s website loading data, the starting load for a 69 gr Sierra matchking in .223 rem is 23.3 gr of IMR-4895, so you are definitely on the low end. They show a max charge of 24.8 gr, so you should be able to carefully work up to that level, or wherever you find best accuracy, reliability and your personal comfort level. Some believe that the .223 data is conservative for rifles chambered for 5.56 NATO and load even heavier. Check out other websites and published loading manuals from Nosler, Hornady, Sierra, Speer and Lyman and be careful.

Thanks. I do think I have room to work up to at least 24 gr. I'll have to work some up and start the testing procedure.

 

[Charlie98]

But H4895 and IMR 4895 are not the same.

I wasn't saying that, but I've found you need less (by weight) H over IMR, so if you are seeing a compressed charge of IMR, you might get there with H... and if there is data there, too, all the better.

75grns is a lot of weight in the AR, I like solid Service Rifle data for it. I understand you can probably safely use .223 data, but that doesn't take into account gas volume which is critical in the AR.

 

[Blackcloud6]

75grns is a lot of weight in the AR, I like solid Service Rifle data for it.

I'm going to use up the stock of the 75 HPBT bullets I have and then probably switch to a different, less heavy bullet.

 

[Laphroaig]

Just curious, with all of the changes that you made, are you now running a Magpul BAD lever?

As for your charge, I'm running 24.0 Rl15 with the Hornady 75's. I love them! I used to load 24.3 IMR4895 with 69 Smk's. I never used it with the 75's though so can't give any advice on your load.

 

[Blackcloud6]

Just curious, with all of the changes that you made, are you now running a Magpul BAD lever?

No I have not installed a Magpul BAD lever.

 

[Blue68f100]

When you replaced the upper you may have not got the gas block alignment with port, not in then same spot. I would recheck that first since these loads worked ok before the swap. Most gas blocks have to be positioned 0.025" from the barrel step. If your happen to move it down against the barrel step you may have partially blocked the port.

 

[Skgreen]

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[Blackcloud6]

Skgreen, thanks.

 

[brasscollector]

After playing around with the 75gr HPBTs for a while I will say my favorite powder for those is 8208XBR. I did try it with H4895 and had good accuracy/velocity but the 8208 was just a bit better, YMMV.

 

[brutus51]

Don't wish to add to the confusion but I ran your recipe through Quick Load with both the Hornady and IMR 4895 and got the following results for what it's worth.
Hornady 23.2 gr 4895 with Hornady 75.gr BTHP bullet = 2684fps. and 60232psi.
IMR 23.2 gr 4895 with Hornady 75.gr BTHP bullet = 2618fps. and 54266psi.
Calculation using 16" barrel with a 1:7 twist.