.223 OAL question

[steve1147]

I know this sounds simple, but sometimes things seem too easy, so here goes!
I worked up a good load for my 5.56 ar-15 using .223 Remington brass, a cci magnum primer, 23.5 gns of H-335, a Hornady v-max 55 gn. bullet w/ an OAL of 2.225, avg. speed of 2735 fps and good enough accuracy for my plinking and skills.
Now, I just bought 500 Midway Dogtown bullets in the same 55 gns, but they're .120" shorter than the v-max.
Am I wrong to assume I'll get approx. the same performance out of these by seating them to an OAL of 2.105 so the combustion space is the same?
Would there be any disadvantages to such a short OAL?
Thanks! Steve W.

 

[zippy13]

A shorter bullet of the same weight must have a different shape. Different bullet shape = difference performance.

 

[praetorian97]

Pics?

 

[steve1147]

Pics added above. My concern is safety (pressure) and functionality (will they cycle dependably) more than hitting a dime at 200 yds. I only use a red dot or laser and seldom shoot over 100 yds.
Thanks!

 

[gregjc9]

Steve, I worked up some very nice loads with the DT 55gr over this past winter. The shot nicely in my RRA AR with 20" Predator Persuit barrel. I tried the VMax, and the DT were much more accurate, for me. If you like, I can post my load data tonight when I get home.

 

[mehavey]

"...good enough accuracy for my plinking and skills...."

With that proviso above, you will be just fine functionally/pressure-wise, and not much different velocity-wise (at your likely ranges of interest).

Your exact POA and most accurate powder/load combination may require adjustment -- depending on what you find w/ the first couple of rounds.



Post: What I find fascinating is the variation in officially-published data that new guys have to deal with:

- Hornady 6th says their 55-grainers (all of them) max out with 23.2gr/H335
- Lyman 49th/Speer 13th say 55gr SP's start at 24gr+/H335 (!)
- My QL says your probable DogTown 55gr-SPs at (Lyman's suggsted) OAL of 2.260" (or even Hornady's 2.200") are producing only 43-44,000psi.

My head hurts.

 

[chasep255]

If the bullet is different then it will shoot differently. I don't know by how much but you will just have to take it to the range and see.

 

[Marco Califo]

Sierra Bullets publishes these loads (223 bolt guns) for ALL their 55 gr bullets, starting to max:

Powder /Velocity 2800 2900 3000 3100 3200 3300
H335 23.0 23.9 24.8 25.7 26.6 27.5

#1345 .224" 55 gr. Blitz
C.O.A.L. 2.250"
#1350 .224" 55 gr. SMP
C.O.A.L. 2.230"
#1355 .224" 55 gr. FMJBT
C.O.A.L. 2.250"
#1360 .224" 55 gr. SPT
C.O.A.L. 2.250"
#1365 .224" 55 gr. SBT
C.O.A.L. 2.250"
#1390 .224" 55 gr. HPBT
C.O.A.L. 2.240"
#1455 .224" 55 gr. BlitzKing
C.O.A.L. 2.250"

 

[Volucris]

I load 55 gr V-MAX rounds in 1.750" trimmed 223 cases for a COAL of 2.250". I use 25.0 gr of H-335 with CCI#400 SR primers in Lake City cases. It's fired in a military spec 5.56 NATO M16 chamber and barrel. No pressure signs and it works quite well. Rather fun turning cans and jugs of water into vapor clouds.


I prefer to listen to Hodgdon's website for their load data for their own powders. The Sierra 223 manual online also works for their AR-15 loads.

 

[Marco Califo]

Sierra 223 AR for the same bullets:
Powder /Velocity 2700 2800 2900 3000
H335 23.6 24.3 25.0 25.7

 

[PA-Joe]

The plastic tip on the Hornady will give them a longer COL. It is the length to the ogive of the bullet that is critical. The ogive is what touches the lands or rifling.

 

[steve1147]

Sorry, but back to the topic, will pressures be about the same and will .223 ammo that short normally function through the mechanism correctly?

 

[wncchester]

Anyone saying he can predict what will follow a change in a reload will likely lie to you about other stuff too.

 

[A_Gamehog]

Just a heads up, those bullets (Lead tipped) when shot at animals, squirrels, p-dogs go completely thru and "keep on going". My friend still uses them on squirrels as we have lots of them left. You can hear the bullet hit solid objects and everything else behind the critter. Use caution. Much better choice is the 55 HP, the makers are now confirmed, they are made by Nosler in Bend Oregon, Midway's website now confirms it.

On your question, rule of thumb, change any componet, re-work the load. Bullet length and shape changes everything.

I use the 34 Grain dogtowns and they are inserted a caliber deep into the case. These are short bullets with a BC of about .115. In my AR-15 it functions very well, no FTF's yet...

 

[Cruz5350]

Grab a Precision Mic from RCBS and go to town. Hornady makes a unit that works very well also.