75 gr .223 ammo . . . increased problems feeding? Yes? No?

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Originally Posted by Mean Bone

[SIZE=3]I'm so dumb I thought this was an intelligent conversation. :D

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It doesn't seem so foolish to me given another recent discussion.

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Originally Posted by Clint

With a bare barrel in one hand and a 115/124 FMJ in your other hand, starting at a 45 degree angle, "drive" it up the feed ramp and around the corner into the chamber.

It will generally feel smooth without much resistance throughout the path.


Then, try the same thing with 147 flat nose.

You'll likely find a large resistance or a sticking point as the cartridge makes the final turn into the chamber.

This is the condition that can be improved by rounding the junction of the feed cone and chamber.


Only do the minimum amount to get good feeding. Excess material removal results in an unsupported chamber and the potential for bad things to happen.

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Originally Posted by Disciple

It doesn't seem so foolish to me given another recent discussion.

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He's talking about pistols here, not to mention flat nose bullets which dont exist in the 5.56/.223 cartridge.

Unless you have bullets that exceed the length where it can't fit into the magazine, bullet weight means nothing when it comes to properly feeding.

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Originally Posted by Mean Bone

Sorry . . . didn't realize I was picking on a scab. Wish I had info regarding OAL, etc. Was sorta wondering if 75 grain bullets approached the limits of OAL thereby making them more difficult to feed in some rifles.

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You didn't, you're fine. Just an opportunity to post a good reminder.

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I'm so dumb I thought this was an intelligent conversation. :D

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It is.

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What I've learned: Having a 75 grain bullet by itself is not an indicator of potential feeding problems. To determine if this particular round will have a problem in my particular rifle I'll need to try it myself. Right? :smile:

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Yep.

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Originally Posted by vicious_cb

He's talking about pistols here, not to mention flat nose bullets which dont exist in the 5.56/.223 cartridge.

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And even in pistols not anywhere near as valid as posted by many folks, without further info.

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Unless you have bullets that exceed the length where it can't fit into the magazine, bullet weight means nothing when it comes to properly feeding.

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Yep.

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Originally Posted by LMT Shooter

I shoot Hornady 75gr BTHP a bit, and their 70gr GMX some, and I've never had an issue at all.

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Same, thousands of them in several rifles, single and mag loaded, never a feed issue at all.

all my rifles have the M4 cut for receiver and barrel extension.


Andrew - Lancaster, CA
NRA Life Member, CRPA member, Calguns.net contributor, CGF / SAF / FPC / CCRKBA / GOA / NAGR / NRA-ILA contributor, USCCA member - Support your defenders!

Pics below are Hornady
75gr ELD
70Gr GMX (has the double cannelure)
73gr ELD
75gr OTM BTHP

Pay attention to third pic showing approximately aligned at seating depth, the 73gr ELD reliably feeds with M4 cuts but the 75gr ELD might not since its tip rubs the magazine wall (not mag length compatible, I single feed them).

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Andrew - Lancaster, CA
NRA Life Member, CRPA member, Calguns.net contributor, CGF / SAF / FPC / CCRKBA / GOA / NAGR / NRA-ILA contributor, USCCA member - Support your defenders!

As long as it’s made by a reputable manufacturer, you shouldn’t have any problems.

I personally use BH 77 grain 5.56 for my chosen round. It runs flawlessly in all of my rifles.

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Originally Posted by Mean Bone

I found some 75 grain HPBT .223 ammo at just over a "buck-a-bullet" when shipping and taxes are included.

My concern is that I may have an increased possibility of feeding problems. At that price I'd rather not find that out on my own (although I may have to).

Do 75 grain rounds have a history in this regard? I don't have an overall length for this ammo.

I'm running a MilSpec 5.56 BCM RECCE16 with an M4 ramp.

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Originally Posted by gaijin

COAL will be magazine length.
I've shot 3 versions of 5.56 77 gr OTM; BH, IMI, Magtech.
No problems.

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Assuming Hornady and Speer load data OAL carries over to their manufactured ammo it isn't always mag length. Looking right now and only the 5.56 pressure 75gr gold dot is shown 2.260" mag length while .223 gold dot and all of the Hornady are listed shorter.

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Originally Posted by lordmorgul

Pics below are Hornady
75gr ELD
70Gr GMX (has the double cannelure)
73gr ELD
75gr OTM BTHP

Pay attention to third pic showing approximately aligned at seating depth, the 73gr ELD reliably feeds with M4 cuts but the 75gr ELD might not since its tip rubs the magazine wall (not mag length compatible, I single feed them).

!

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Hornady load data shows the 75gr ELD as 2.390" oal and (odd to me) the 73gr ELD and std. 75gr bthp as 2.250" instead of 2.260" the typical max mag length.

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Originally Posted by vicious_cb

He's talking about pistols here, not to mention flat nose bullets which dont exist in the 5.56/.223 cartridge.

.

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Normally yes, but cast bullet molds for .223 are almost entirely flat nose. On the positive. Been looking in to casting and coating them and videos of guys demonstrating it shows AR's feeding them as good as anything else.

99% sure I have seen factory compressed copper/fragmenting bullets that were flat nose and some lighter weight hollow points may as well be considered flat nose as well.

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Originally Posted by jsbhike

Hornady load data shows the 75gr ELD as 2.390" oal and (odd to me) the 73gr ELD and std. 75gr bthp as 2.250" instead of 2.260" the typical max mag length.

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Yes that’s accurate, Of course you do not have to follow that exactly, but what works well for your load and gun starting low.

I load them at these lengths, but offer no suggestion it is optimal or better than their recommended max COAL. Point of fact I load every Hornady bullet I’ve got (4 more variants) slightly shorter than their own listed max COAL, and closer to or even shorter than Hornady loads it themselves, which as you posted above is shorter than limit.

75 ELD at 2.350”
73 ELD at 2.260”
70 GMX at 2.200”
75 OTM at 2.220”

I did try loading the 75gr ELD at mag length just barely touching the mag wall, it definitely cannot be crimped if that is done since the ogive is then starting well inside the case neck and I would not recommend (and won’t myself) loading that way again since even though I don’t crimp any of them the neck tension provided friction is reduced a lot with less bearing surface in contact with bullet. (And it would have a good chance of asymmetrically crimping or getting stuck on feed ramps when loading)

Andrew - Lancaster, CA
NRA Life Member, CRPA member, Calguns.net contributor, CGF / SAF / FPC / CCRKBA / GOA / NAGR / NRA-ILA contributor, USCCA member - Support your defenders!