Any love here for the 75gr Hornady BTHP (or loaded TAP round) in 1:8 twist barrels? How do they shoot?

I've been working up some loads the last few days, but couldn't get to a longer range yet (only 25 yds at home) so it was just about finding max load and will work on accuracy from there. I'm pleasantly surprised with the velocity I can get from this one, compared to the other 77gr stuff and the 69gr TMK, but don't know how it will shoot yet.

Have not fine tuned anything but I threw together some 75hpbt loads at 2.250 and they showed promise out of a stag 1/8 barrel. Groups were an inch and change but I know it can get better.
I realize that's not much help but to say they worked no problem for me

They shoot good for me. TAC, RL-15, and Varget work well with them.

24gr of TAC has been a good load in all my guns.

Yep.

Like a mofo.




dave

24.2 TAC was a generic load with 77 smks for a bunch of different team guns years ago.. accurate enough by far to take to nationals....

The 75s used to be a bit sensitive about high pressures, but other than that were fine.

I got good pricing on them for years, and as such have a lot laying around loaded up with RL15. They have killed lots of critters...

I found it interesting that Ramshot's published 5.56 data for TAC and 2460 show one full grain and ~100 fps more for the 75gr BTHP compared to the 77gr SMK. My own load development shows similar results; I'm able to push the 75gr to the same speed as the 69gr TMK or SMK, ~2800 fps from my 16" 1:8. TAC, 2460, and Benchmark all achieved that. Varget is often recommended, but was about 200 fps slower.

That really doesn't make much sense based on the length of the bearing surface of the various bullets.

Here are the bearing surface length's on several of the bullets mentioned:

75 Hornady OTM = 0.408"
77 Sierra TMK = 0.425"
77 Nosler CC = 0.420"
69 Sierra TMK = 0.337"
69 Sierra SMK = 0.315"

Based on the bearing surface comparison, I can't see much reason for powder charges to be much different for the Hornady compared to either of the Sierra 77 grain bullets & I am using the same charge of AR Comp for all 3........velocities for all 3 are within 25-30 FPS of each other in the same gun.

However, that's a 3% difference in bearing surface, so straightlined on a 23 grain powder charge that could be a .69 grain powder weight increase for the Hornady..........maybe.

Varget will get as much velocity with 77's as just about anything else if you load it up to it's capability, so will RL-15..........highest velocity might always = best accuracy though.

8208XBR is an excellent powder but falls a little short on velocity compared to the others above but it's generally pretty accurate.

MM

Look at Western Powders/Ramshot's 5.56 data, it's pretty clear. They list charges for the 75gr Hornady BTHP a full grain higher than the 77 SMK with their four most appropriate powders; obviously those two bullets build pressure differently.

There's more to it than just bearing length. Jacket thickness, core hardness, etc.

Varget ran into pressure signs about 200+ fps before the other powders I mentioned, in my testing this weekend. It wasn't even close, and the difference was very clear. All the same components except powder, and the velocity I was getting with Varget are in line with what I've seen reported online too.

Yeah, I checked their website.......I don't use any of those powders though.

Maybe I'm light on my 75 Hornady loads

Unfortunately, there's not much data available for AR Comp.......but Alliant does list both the Hornady & the Sierra 69 & a heavier charge is listed for the Hornady bullet there just as a comparison so maybe there really is that much difference.

Sure would like to have a pizzeo system.

Maybe I'll check hardness on a few bullets, just for the helluvait.

MM

Yeah, you can get more speed out of the 75 but it never was accurate enough for me at those higher speeds.... YMMV as it does with a lot of opinions here.

Yep I got more speed out of them than SMK's too, took more powder, got more speed and shot bigger groups. I quit messing with them at the time and switched to NCC's but they sucked too, accuracy wise. Nothing came close to SMK's for accuracy.

That said, there's nothing wrong with them for a hunting round. It's not like they were M855's or anything that crazy.

That's been one of my questions. I'll find out soon.

I don't have any desire to run heavy bullets slow; if that's what they take I'll stick with my proven loads with 65 and 69 gr Sierras moving fast.

I couldn't get the 77gr Nosler to shoot well in this barrel at all; 2"-3" groups @ 100 no matter what.

This is a set of tests I ran a few weeks ago with 3 different powders using Nolser 77 gr CC's & Sierra 77 gr TMK........1st trials with the TMK's.

Not much difference in this particular gun with either bullet & not much difference between the powders, pending larger scale tests; the POI differences are pretty consistent too with all 3 powders, the Nolsers in a slightly different POI from the Sierras.

The Nolsers are sufficient for most of my routine needs; for that matter so are the Hornady's. Not sub-MOA, but close enough for most tasks.

MM

OK, checked my notes again - 24.0gr of Varget with the 75gr Hornady did 2,535 fps for 5 shots, and seemed to be pretty much max.

24.5gr (1/2gr under published max) of AA2460 did 2,820 fps, and 25.0gr of TAC did 2,800. Pretty big difference from Varget.

Benchmark was in the middle, at 2,675 avg, possibly a little wiggle room to work up, depending on accuracy. Will have to work with that one more.

MontanaMan, thanks for sharing. Honestly though, if these Hornady 75's shoot like that for me, I'll go back to my 65 and 69 gr loads, that shoot groups about half that size or better. What you posted is probably "good enough", but I don't see the trade-off in accuracy being worth the slightly better ballistic coefficient, if that's what I end up with.

Try the regular old SMK's before you give up on 77's. The TMK's didn't work for me any better than the NCC's.

And yes Varget sucks.

Berger 77 OTM's have shot good for me. I haven't chrono'ed yet, though.

The Berger Tactical 77 gr OTM is reputed to be the best of the bunch & it's definitely on my list to test but I don't have any of them yet.

Might be OK for special occasions, but they're pricey for everyday use but I could easily justify them for 200 yard egg shooting if they are as good as everyone has said.

We'll see. Not too concerned about the velocity, to a certain point.

With the other better, easier metering powders available today, there's not a lot of need for Varget.......it's bulky & shears too much in the powder feeder.

MM

Varget doesn't give the best velocity but it's the powder that's given me the best accuracy. However, I still use mostly TAC for the 75/77gr bullets as it's still pretty accurate and gives a better velocity.

24gr TAC pushes the 75gr 2750fps from my 18" barrel.

Varget was all we had years ago... it got the job done.

its still a fall back load too... 25 to 25.5 Varget, LC case, BR4 primer and 69 SMK not tipped at 2.250... if your barrel didn't shoot that one in small groups there was an issue....

It might have been part of a blind load on a brand new barrel of mine for 200-300 yard part of a match where I set a range record.... LOL...

Me too within reason, but my only goal in using the heavier bullets is for longer distance, and velocity does matter. If it comes down to running a 75/77gr at 2500 fps vs my already proven load of the 65gr SGK at 2950, the choice is easy with no real advantage to the heavy bullet that I can see.

Some guys talk about velocity vs accuracy as if you have to choose one or the other, but this is 'Merica, dang it, and I can have both. If I can get good accuracy with the 75gr at 2700-2800 fps, I'll be pretty happy.

Since I've got a lot of 69's on hand, I guess I'd have to say that I pretty much agree.

MM

Figured I'd follow up on this.

After a bunch of testing (~150 rounds of 75gr Hornady + other bullets) I've settled on 23.5gr of Benchmark with the 75gr BTHP Hornady for 2,675 fps from my 16" barrel. Best accuracy seems to be with S&B SR primers, of all things, with CCI 400 following pretty closely.

As posted above, I could push that bullet another 150 fps faster, which would help a little at distance, but the accuracy wasn't there. Trying to push the 77gr Nosler or Sierra faster didn't pan out either, running into pressure signs and bad accuracy sooner with both.

At 2675, it's still a good 150 fps faster than my barrel will do with Varget, and accuracy is good both bare and suppressed, generally around 0.5 moa for 5 shots. It seems to shoot consistently too, with different holds on the gun, weather, and bore conditions, which is more important to me than tiny groups when conditions are perfect.

I've given up on the 69 TMK for now, even though it can fly flatter with less wind drift at distance with the velocity I'm getting; it's just too inconsistent in my barrel. Some days I saw really promising groups, but the next day the same load might go into 1.5-2".