Opinions on OAL for .223 Bolt Gun

[D.A.T]

I have a Hornady OAL gage and did some measuring on my .223 Savage PC. 20" 1/9 Twist.

The Mag. Length is around 2.42

Hornady 75 Gr. A-Max hit the lands at around 2.55, Hornady manual reccomends 2.390. Should I load to max mag length?

Also Hornady 68 Gr. hits the lands at around 2.428 and Manual recomends 2.250. What would be a good length?

I have not yet confirmed that the 75 Gr. will stablize in my barrel. I figured pushing them to a higher speed would help with that and loading them as long as possible would make help in that reguard.

 

[FCS]

Re: Opinions on OAL for .223 Bolt Gun

Load'em 0.040" off the lands, or 0.010" under mag constraint and carry on.

75 A-max from a 9 twist is iffy, some lot #s of the 75 A-max will stabilize and some will not. 75 JLKs have run very reliably for me from several factory 9 twist barrels. 70 Berger VLD would be a very solid choice also.

I like the 75 A-max but when you get the first lot # that is a bit longer and won't stabilize, it gets real frustrating real quick. I've pretty much gone to only using the 75 A-max in an 8, or faster, twist barrel. You can't push'em fast enough to make up for lack of needed twist.
You'll hear that guys have made the 75 Amax run from a 9 twist, I have also. Problem is you get a new lot # and it doesn't stabilize then you have X number of bullets that are not useful until you rebarrel to a faster twist.

YMMV

 

[D.A.T]

Re: Opinions on OAL for .223 Bolt Gun

Think I am wasting my time chasing the 75 A-Max dream then?

The longest I could go would be the .01 under mag length for the 68gr.

The Bergers are about $10.00 more per 100 then the Hornady, are they really worth that much of a difference?

 

[Fuzzball]

Re: Opinions on OAL for .223 Bolt Gun

<span style="font-style: italic">"Hornady manual reccomends 2.390..., Hornady 68 Gr... Manual recomends 2.250."</span>

Manuals <span style="font-style: italic">reccomend</span> no OAL, they simply tell us what they used when compiling the listed data, what we do is up to us. Seems most factory rifles shooting common bullets do best with a jump between 20 and 40 thou.

 

[BoilerUP]

Re: Opinions on OAL for .223 Bolt Gun

That's a reeeeeeeeeeeal long throat in your barrel if a 75gr A-Max is on the lands at 2.55" and a 68gr HPBT at 2.428"....

I believe Savage's 223 Remington barrels have 0.025" freebore, and my 26" 1:9 223 Rem Savage 12FV barrel puts the 75gr A-Max into the lands at 2.465" OAL.

75gr A-Max with 24.5gr Varget in Nosler brass @ 2.46" OAL gives me about 2950fps from my 26" barrel. I haven't fine-tuned the load yet, but at 500' ASL/85F has provided consistent sub-0.6" 5 shot groups at 100yd and through a clean barrel (not ideal for accuracy) put 5 shots into 0.7MOA @ 200yd.

I believe there's more accuracy to be had...a combination of me getting better behind the trigger and dialing in the load.

The 75gr HPBT, on the other hand, is sub-half MOA at 200yd from the same barrel at 2860fps. Loading to AR mag length (2.25") works pretty well, but my barrel likes 2.28-2.30".

 

[Cegorach]

Re: Opinions on OAL for .223 Bolt Gun

I couldn't get the 75 a max to work in my 20" 9 twist 223, even after I had the chamber punched out to AI.

Since then I have settled on the 70 vld which has good performance and assured stability.

 

[D.A.T]

Re: Opinions on OAL for .223 Bolt Gun

I had to load the 68 Gr at 2.265 OAL to function in the mag. I went from 2.4 down.

I loaded up some with 25 Gr. of Varget and some with 25.5 Gr. I will get some speeds and groups tomarrow.

Since I have a longer then normal OAL I should be able to approach mag loads (around 26 Gr.) easier RIGHT?

 

[D.A.T]

Re: Opinions on OAL for .223 Bolt Gun

What speed range should I be around? 20" Bolt Gun with 68 Gr.? Should I be able to Hit 2900?

 

[D.A.T]

Re: Opinions on OAL for .223 Bolt Gun

If I hit 2900 that should put me supersonic untill 900 Yds, which is more then this gun will ever be ran at 95% of the time.

I want this for mostly 600 Yd and closer gun.


3000 FPS would take a Mil of 1K drop I doubt that is possible without having an AI chamber

 

[Cproflow]

Re: Opinions on OAL for .223 Bolt Gun

I load mine to 2.443" using an AI mag in my TIkka T3 (which is 1 in 8" twist). using 24.6 gr varget I'm getting 2755 fps and sub-MOA

 

[D.A.T]

Re: Opinions on OAL for .223 Bolt Gun

What length of barrel?

That seems kinda slow for an AI

 

[Cproflow]

Re: Opinions on OAL for .223 Bolt Gun

20" barrel.

It isn't an AI actually...it's standard .223. The magazine is an Accuracy International mag--so it is mucho long, which lets you get that nice COL for the 75 gr Amax.

I thought most of the OPs focus was on COL, so I thought it made sense to mention the Accuracy Itn'l mags allow those bullets to work so well.

Sorry if I confused you with Ackley Improved--that happens to me sometimes too

 

[D.A.T]

Re: Opinions on OAL for .223 Bolt Gun

Have you tried more Varget then that? I figured you could add some more with that super long COL

 

[Boxerglocker]

Re: Opinions on OAL for .223 Bolt Gun

I'm running a 69 SMK with 25.4g of Varget at 2.265 OAL out of my Remington 700 SPS Tactical 20 incher 1-9 twist, stock bottom metal. Using once fired FL sized and trimmed LC brass it does sub MOA and once form fired and neck sized only (0.002-0.003) the groups get even tighter.

 

[easternncnative]

Re: Opinions on OAL for .223 Bolt Gun

I'm working on the same issue with 75 gr AMAXs in my Rem 700 TAC. First time out with them produced buckshot groups. Figuring that they must be sensitive to seating depth, I've set up this quick trial to see if I can get a clue what the hell is going on. Seating depths range from 0.005" to 0.035" off the lands. Soon as I can get to the range, I'll post results.

 

[BoilerUP]

Re: Opinions on OAL for .223 Bolt Gun

75gr A-Max may or may not stabilize in a 1:9 barrel.

They seem to do okay (10 shot 0.61" @ 100yd, 5 shot 1.2" @ 200yd) in my 26" 1:9 Savage barrel @ 500' ASL, 80°F, and 2930fps...which 'Shooter' app says provides a stability factor of 1.01.

 

[easternncnative]

Re: Opinions on OAL for .223 Bolt Gun

77 grain SMKs shoot like the proverbial laser out of my 1:9 Rem 700 TAC.

I am stumped as to why the Hornady 75 grain AMAXs behave so differently out of the same gun.

 

[BoilerUP]

Re: Opinions on OAL for .223 Bolt Gun

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: easternncnative</div><div class="ubbcode-body">I am stumped as to why the Hornady 75 grain AMAXs behave so differently out of the same gun. </div></div>

77gr SMK is 0.116" shorter than the 75gr A-Max and has a tangent ogive, while the A-Max has a secant ogive (more VLD style).

In a 1:9 barrel at 500' ASL elevation and 50°F, the 77gr SMK @ 2860fps has a stability factor of 1.42, while the 75gr A-Max @ 2950fps has a stability factor of 1.01.

Berger 75gr VLD @ 2915fps is 1.15, and the 80gr SMK @ 2700fps is 1.18...

 

[easternncnative]

Re: Opinions on OAL for .223 Bolt Gun

Thank you sir. Are these calculations from QuickLoad..........which I've put off purchasing for too long ???

........or more likely from Point Mass ???

 

[Boxerglocker]

Re: Opinions on OAL for .223 Bolt Gun

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: easternncnative</div><div class="ubbcode-body">77 grain SMKs shoot like the proverbial laser out of my 1:9 Rem 700 TAC.

I am stumped as to why the Hornady 75 grain AMAXs behave so differently out of the same gun. </div></div>

Would you mind sharing your 77 SMK load? I have a few hundred under the bench that eventually get around to loading.

 

[easternncnative]

Re: Opinions on OAL for .223 Bolt Gun

Varget- 23.5 grains
IMR 4064- 23.5 grains

Both get the 77 gr SMKs to ~2675 fps out of my gun.

 

[D.A.T]

Re: Opinions on OAL for .223 Bolt Gun

So I should try some 77 SMK.....Anyone ever report problems with them stablizing in 1/9 twist?

 

[easternncnative]

Re: Opinions on OAL for .223 Bolt Gun

Took the Hornady 75 AMAXs to the range today. No groups with any seating depths, some indications of near keyholing.

My Rem 700 TAC, 1:9, 20" barrel just won't stabilize them.

Now returning to 69 gr SMKs and 77 gr SMKs.


<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: easternncnative</div><div class="ubbcode-body">I'm working on the same issue with 75 gr AMAXs in my Rem 700 TAC. First time out with them produced buckshot groups. Figuring that they must be sensitive to seating depth, I've set up this quick trial to see if I can get a clue what the hell is going on. Seating depths range from 0.005" to 0.035" off the lands. Soon as I can get to the range, I'll post results.

</div></div>

 

[CDAT]

Re: Opinions on OAL for .223 Bolt Gun

DAT, my Rifle is a Rem 700 SPS Tac .223, HSP Stock, CDI Bottom Metal w/AI Polmar Mags and my go to load is as follows:

77 SMK
CCI 400 Small Rifle Primers
23.7 gns of Varget
Brass, what ever I have preped (FC, LC, Win, etc, dose not seem to matter)
OAL = 2.280 (can go even longer w/ Polmar Mags if needed)
AV = 2679-2683 out of a 20 inch barrel

This load is not a barn burner, but at 100 yards I can print a ragged five round hole when I'm having a good day. And it gives good performance from my rife out to 750 yards (head shots on a LaRue at 500 yards are not difficult).

Also, last summer, just for S&G, I tried some Hornady 75 Amaxs and Varget loads. To say I and was less than pleased with the outcome is an understatement. Aparently the 75 Amax bullet did not like the 1 in 9 twist in my rifle barrel. I've seen better groups from a shot gun----nothing under 2 inches at 100 yards.

CDAT

 

[dbateman]

Re: Opinions on OAL for .223 Bolt Gun

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: D.A.T.</div><div class="ubbcode-body">So I should try some 77 SMK.....Anyone ever report problems with them stablizing in 1/9 twist? </div></div>

My 9 twist Rem sps tac stabilises them just fine and there are a fair few others that do as well but there are some that won't.

But there are enough that do that its worth a try.

 

[1Sg (ret)]

Re: Opinions on OAL for .223 Bolt Gun

Hey DAT i am a DAT myself.My SPS tac will shoot the hell out of 77SMKs.I load win brass, 23 gr of AA2230,and wsr.As long as i can get em in the mag.And like CDAT I have made head shots out to 600 on steel.