68gr vs. 75gr

[jLorenzo]

I am playing around with a ballistic calc and am seeing the 68 has considerably less drop and only around .1 more wind, at least under 1000 or so.
Using 2700 fps for the 75 and 2940 for the 68.
Anyone have experience with the 68s (Hornady bthp)? Most of my shooting will be inside of 600y with an 18" AR.

 

[RldrNewby]

Been awhile since I shot them, but they shot great for me. Didn’t try pushing them out past 600 much, but I did with 77gSMKs and got impacts on steel at 1000.

The pic below was one of the first few workups with Lapua Brass. 23.2 - 23.4 was where I wanted to load, but had more ejector swipes than I liked, so ended up running 22.8. Swapped lot of powder and picked up a really random swipe at 22.8, so settled on 22.6. Can’t remember MV, but it’s not impressive being a 16” barrel. Shoots awesome out of my rig tho.

 

[rweaver00geo]

My testing mirrors RldrNewby.
With the 68, 8208 and Nammo brass I thought 22.8 to 23.3 was where it was at. Out of an 18" the numbers for 23.3 was 2737 SD of 7.5 unfortunately I have exhausted my supply of 8208 so its back to Varget.
The 75, 23.2 grains of 8208 in Lc brass ran 2680 and the SD averaged 12

​

 

[BCP]

I am playing around with a ballistic calc and am seeing the 68 has considerably less drop and only around .1 more wind, at least under 1000 or so.
Using 2700 fps for the 75 and 2940 for the 68.
Anyone have experience with the 68s (Hornady bthp)? Most of my shooting will be inside of 600y with an 18" AR.

They're both fine the velocity difference isn't that big though. Like the guy posted above you will gain maybe 50fps.

 

[Milo 2.5]

IME, the weight difference between 68gr and 75gr bullets really surfaced between 500 and 600 yards. I ran 68gr Hornady;s for yrs, but if you have the twist to spin 75's, no logical reason not to.
Both low BC bullets, it is not nailing the wind call, it is controlling the vertical. Heavy wins.

 

[TxWelder35]

Playing with cfe223 and 75s out of my 18” AR 2 weeks ago.
25.6gn of cfe In LC brass.

 

[jLorenzo]

Playing with cfe223 and 75s out of my 18” AR 2 weeks ago.
25.6gn of cfe In LC brass.

View attachment 7665254View attachment 7665255

I have a pound of CFE thats on my list to try next with the 75s in my 18" AR. Best Ive done is 2714 with 24.3gr of RL15, SD of 7, I dont want anything close to pressure in my AR. Id rather have longer brass life. Varget is accurate but much slower. What altitude and temp were those shots taken? Velocity data looks real good on that load. I also have a bunch of Frontier brass but I havent tried reloading it yet. The newer Frontier ammo Ive bought has actual LC brass now which is nice. How does that load group?

 

[TxWelder35]

I have a pound of CFE thats on my list to try next with the 75s in my 18" AR. Best Ive done is 2714 with 24.3gr of RL15, SD of 7, I dont want anything close to pressure in my AR. Id rather have longer brass life. Varget is accurate but much slower. What altitude and temp were those shots taken? Velocity data looks real good on that load. I also have a bunch of Frontier brass but I havent tried reloading it yet. The newer Frontier ammo Ive bought has actual LC brass now which is nice. How does that load group?

Didn’t shoot for groups but had zero issue putting them all in the same impact mark on steel at 250, and no problems hitting out to 600.

90f at 700’ ASL roughly.

these loads were definitely on the hot side given the ejector marks but nothing that was scary based on the brass.

that is 150fps faster than I can get out of 8208 and 2520 with the same marks on the brass.

going out again tomorrow, I’m going to back down to 25.4 and see what that does, maybe it’ll clear up some of those ejector marks.

curious to see what your results are with the CFE, I wasn’t expecting it to be such a speed demon out of my rifle when 8208 and 2520 gave me at most 2750.

brass life isn’t super important to me, 223 LC brass isn’t too hard to come by. Ended up bringing 100 pieces back with me from the range last weekend. If I get 4-5 firings out of it I’m pretty happy.

 

[jLorenzo]

This guys experience with Varget matches mine but he got different results with RL15 than I did. I have an 18" WOA spr barrel and so does he in most of these vids. I test powder charges over the labradar without worrying about groupings, I have to mess with seating depth next. Found single digit SDs with 23.4 of RL15 and Hornady 75s, right around an MOA. Going to try Sierras 77 also.

 

[TxWelder35]

Didn’t shoot for groups but had zero issue putting them all in the same impact mark on steel at 250, and no problems hitting out to 600.

90f at 700’ ASL roughly.

these loads were definitely on the hot side given the ejector marks but nothing that was scary based on the brass.

that is 150fps faster than I can get out of 8208 and 2520 with the same marks on the brass.

going out again tomorrow, I’m going to back down to 25.4 and see what that does, maybe it’ll clear up some of those ejector marks.

curious to see what your results are with the CFE, I wasn’t expecting it to be such a speed demon out of my rifle when 8208 and 2520 gave me at most 2750.

brass life isn’t super important to me, 223 LC brass isn’t too hard to come by. Ended up bringing 100 pieces back with me from the range last weekend. If I get 4-5 firings out of it I’m pretty happy.

Following up on this, went out yesterday in similar conditions with 25.3gn of cfe223 under a 75gn hpbt and got 2820 FPS out of my 18” stainless proof barrel