.223 pressure Gold Dots from a 14.5" barrel

[ABNAK]

The fact that they are .223 pressure and not 5.56 NATO kind of bugs me. I saw Molon's thread where he chrono'd the 64gr GD and it got 2588fps average from a 14.5" barrel. Since most of my AR's have that length of barrel that is what I will base my decision on.

I ran a ballistics calculator with the 64gr's BC of 0.27 at 2550fps. If the velocity threshold for expansion is 1800fps then you *should* get it out to ~ 210 yards out of a 14.5" barrel. Sound right? Certainly not stellar but doable I guess.

*If* I order some Gold Dots I'm leaning towards the 64gr pill. It would seem that the 75gr would be handicapped by an even lower MV and therefore hit the 1800fps threshold way sooner than 210 yards.

My current go-to for my AR's is Mk318.

One more question: how is cycling in guns set up for 5.56 NATO rounds? Some of my AR's are mid-lengths and a couple are carbine length gas systems but all have H2 buffers. Standard springs (i.e. not Sprinco's or such). Two of them have LMT Enhanced BCG's. Need to change anything by going to .223 pressure loads?

[vicious_cb]

The fact that they are .223 pressure and not 5.56 NATO kind of bugs me. I saw Molon's thread where he chrono'd the 64gr GD and it got 2588fps average from a 14.5" barrel. Since most of my AR's have that length of barrel that is what I will base my decision on.

I ran a ballistics calculator with the 64gr's BC of 0.27 at 2550fps. If the velocity threshold for expansion is 1800fps then you *should* get it out to ~ 210 yards out of a 14.5" barrel. Sound right? Certainly not stellar but doable I guess.

*If* I order some Gold Dots I'm leaning towards the 64gr pill. It would seem that the 75gr would be handicapped by an even lower MV and therefore hit the 1800fps threshold way sooner than 210 yards.

My current go-to for my AR's is Mk318.

One more question: how is cycling in guns set up for 5.56 NATO rounds? Some of my AR's are mid-lengths and a couple are carbine length gas systems but all have H2 buffers. Standard springs (i.e. not Sprinco's or such). Two of them have LMT Enhanced BCG's. Need to change anything by going to .223 pressure loads?

No, the 75gr Gold Dot will hit 1821 fps at 300 yards. The 64gr Gold Dot with its lower BC will hit 1838 fps at 250 yards out of a 14.5" barrel. I havent shot 64gr Gold Dots for a long time but the 75gr's have a weird pressure curve, it ejected more like 5.56 than .223 even with an A5 system.

[ABNAK]

No, the 75gr Gold Dot will hit 1821 fps at 300 yards. The 64gr Gold Dot with its lower BC will hit 1838 fps at 250 yards out of a 14.5" barrel. I havent shot 64gr Gold Dots for a long time but the 75gr's have a weird pressure curve, it ejected more like 5.56 than .223 even with an A5 system.

Okay, so basically a 50 yard difference in expansion threshold from the 14.5" barrel, correct? (advantage going to the 75gr)

ETA: I assume the 1821fps/300yds velocity you mention for the 75gr is from a 14.5" barrel also, right?

[vicious_cb]

Okay, so basically a 50 yard difference in expansion threshold from the 14.5" barrel, correct? (advantage going to the 75gr)

ETA: I assume the 1821fps/300yds velocity you mention for the 75gr is from a 14.5" barrel also, right?

Yes, using a 14.5" for both.

[WS6]

No, the 75gr Gold Dot will hit 1821 fps at 300 yards. The 64gr Gold Dot with its lower BC will hit 1838 fps at 250 yards out of a 14.5" barrel. I havent shot 64gr Gold Dots for a long time but the 75gr's have a weird pressure curve, it ejected more like 5.56 than .223 even with an A5 system.

I remain conflicted. I averaged MV for the 75gr GDSP at muzzle, and at 100 yards. The calculated BC was 0.3X (low .3's if I recall).

I also know a guy who averages velocities with better equipment at muzzle vs. 400 yards, and he has said that CONSISTANTLY the Gold Dot's in various calibers clock slower than stated BC by a significant margin. He has tested his techniques against Bryan Litz's numbers, and is usually no more than 0.01 or so off, averaged over a couple of outings, once he corrects for environmentals, so when he is telling me he is getting GDSP's at stuff like 0.05 less than they should be...I am taking note.

Hornady uses Dopplar to track their projectiles. The 70gr GMX is in the mid/high 0.3's. The GDSP is listed as 0.4...I've pulled both projectiles, and I'm sorry...ONE of them be a...hyperbole.

Another great example is the 165gr .308 GDSP. The BC listed for it is 0.446. The BC Sierra lists their 168gr SMK at it 0.462. I'm sorry...I am just NOT seeing it from the GDSP, again, looking at both.

[WS6]

The fact that they are .223 pressure and not 5.56 NATO kind of bugs me. I saw Molon's thread where he chrono'd the 64gr GD and it got 2588fps average from a 14.5" barrel. Since most of my AR's have that length of barrel that is what I will base my decision on.

I ran a ballistics calculator with the 64gr's BC of 0.27 at 2550fps. If the velocity threshold for expansion is 1800fps then you *should* get it out to ~ 210 yards out of a 14.5" barrel. Sound right? Certainly not stellar but doable I guess.
More conflict. They state the 62gr round has a BC of 0.31. It is EVER SO SLIGHTLY SHORTER in the "barrel" part of the body. Sorry, that does not equal a HIGHER BC. I think Federal's BC's are all wet. And I am a huge Federal fan, so no hate here.

*If* I order some Gold Dots I'm leaning towards the 64gr pill. It would seem that the 75gr would be handicapped by an even lower MV and therefore hit the 1800fps threshold way sooner than 210 yards.
Depends on the distance, but those 75gr pills are doing nasty things, So far the longest hit on game I am aware of with a recovered bullet is around 150ish yards from a 16" gun. It expanded with a LOT of room to spare on the velocity/threshold table.

My current go-to for my AR's is Mk318.
Nothing wrong with it.

One more question: how is cycling in guns set up for 5.56 NATO rounds? Some of my AR's are mid-lengths and a couple are carbine length gas systems but all have H2 buffers. Standard springs (i.e. not Sprinco's or such). Two of them have LMT Enhanced BCG's. Need to change anything by going to .223 pressure loads?

The 75gr Gold Dot is the most violently cycling round I have ever fired, including:

IMI 77gr
Hornady T2
70gr Browntip (clocked 2900fps from my 16" gun)
M855A1 (averaged around 3040ish from my 16" gun)
M855
All the other Gold Dots
77gr TMK

75gr Gold Dot kicked harder, and cycled the action more briskly than any of the others. If your gun will only run ONE round because it's so undergassed or you keep turning the gas-block adjustment down, it's likely to be the 75gr GDSP, lol!

[ABNAK]

The 75gr Gold Dot is the most violently cycling round I have ever fired, including:

IMI 77gr
Hornady T2
70gr Browntip (clocked 2900fps from my 16" gun)
M855A1 (averaged around 3040ish from my 16" gun)
M855
All the other Gold Dots
77gr TMK

75gr Gold Dot kicked harder, and cycled the action more briskly than any of the others. If your gun will only run ONE round because it's so undergassed or you keep turning the gas-block adjustment down, it's likely to be the 75gr GDSP, lol!

Thanks for the input!

[WickedWillis]

Tag for info

[fz1boxer]

Yes, using a 14.5" for both.

Looks like the speer is running 5.56 pressures,i have noticed the same abrupt recoil similar to hornady t-2, i have not seen any signs of presure like t-2(primers)

[WS6]

Let me just put it this way: The bullet on the left is the Hornady 70gr GMX. Hornady states that it has a BC of 0.350. The bullet on the right is the 75gr Gold Dot, which is listed as having a BC of 0.4.

Now, I'm no Bryan Litz, but...