A few questions about the 223?

[stuff]

1. What twist rate for 75-80gr bullets?
Berger's twist rate stability calculator thinks I need a minimum of 1:7.2 @ sea level, 32*F, 2850fps for any of their 80gr bullets. Do I really need a 1:7 for the 80s? I've known people run the 90s with 1:7, 80s with 1:8, and 75s with 1:9.

2. What is the actual length of the Hornady 75gr and 80gr ELD-m bullets?
JBM ballistic calculator only has the 75-80gr A-max length @ 1.162" for both bullets. That didn't sound right to me. Twist calculator says 1:6.8 twist for that length.

3. Will 5R rifling increase velocity by 50-75 fps? Will the 5R be easier on the bullets with such a fast twist? Is it worth trying to find or custom order a 5R 1:7?

4. Wyatts Outdorrs DBM and magazine system, anyone ever use one? COAL is 2.850", the plastic AI mags are 2.550". With the Wyatts mag you could really seat those bullets long or not have to single load the 90gr bullets. Wyatts is also a Remington 700 bdl drop in installation.

Thanks

 

[BoilerUP]

Given a choice, I'd always choose 1:7 for 80s and would choose 1:7.7 over 1:8...though I acknowledge plenty of people rock the 80gr VLD from 1:8 without issue. I've run the 90gr Berger VLD @ 2750fps from a 1:7 barrel and they've shot fine.

The lot of 80gr Amax I am shooting currently measure 1.154" long. In a 1:7 barrel, at 2800fps, 500' ASL elevation/59F/29.92Hg/0% humidity my stability factor is 1.57.

 

[Juggerxxx]

Take a look in reloading section for the 73gr and 75gr ELD thread. Has some good info you are asking about.

 

[SEMO Shooter]

I have a 223 with 1:9 twist. It shoots 77 gr SMKs great at 100-200 yards. Bullets are no longer stable after 200 and groups really open up from 300 on. I have the Wyatts DBM on the rifle. The mags do allow you to load long. The feed lips are a bit sharp and it's easy to cut your fingertips trying to get that 10th round in the mag. My rifle does feed/function well with the Wyatts DBM.

I will have a different rifle soon with 1:7 twist for shooting heavier bullets. I'll be using different bottom metal with it so I will have to use poly mags. I hope the shorter COAL works. My previous loads were all 2.26 or just a bit longer.

 

[Rob01]

Just started reloading the 75 ELD with a 7.7 twist and it works very well. I tried the 75 BTHP in the old original factory 9 twist barrel and they did not work at all.

The OAL of the 75 ELD is 1.120". Below is a pic of it next to one of my loaded rounds which is 2.467" OAL and sitting .020" off the lands. Fit perfect in the MDT .223 mags which allow up to 2.550". (sorry about the cat hair in the pic. They like to visit the gun room LOL)

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[long range sponge]

Rob, what velocity are you getting? Barrel length? Might burn through a barrel pretty quick but those would be fun in a 22-250 or a 22 nosler bolt gun.

 

[entropic86]

I shoot 90 SMKs out of a 6.5 twist rock creek. People say they get away with a 7 twist, but who knows when a longer, better bullet will come along. The extra twist makes sure you're stable transonic anyway. I've had them out to 1100 with good results too and had 3 consecutive hits on a 2/3 IPSC steel target in some gusty winds the other day. Switching back to my 243AI still reminds me that there is no replacement for displacement.

 

[Rob01]

Don't have my load book with me but it's a 20" barrel and I think I remember the Varget being in the 2750fps area and the CFE223 around 2700.

 

[stuff]

Given a choice, I'd always choose 1:7 for 80s and would choose 1:7.7 over 1:8...though I acknowledge plenty of people rock the 80gr VLD from 1:8 without issue.

The lot of 80gr Amax I am shooting currently measure 1.154" long. In a 1:7 barrel, at 2800fps, 500' ASL elevation/59F/29.92Hg/0% humidity my stability factor is 1.57.

Well it seems Like a 1:7.7 would work, not ideal, and I may sacrifice some BC. I think l am going to stay on the safe and stable side. I'll be purchasing a 1:7. Thanks for the info on the Amax length.

 

[stuff]

I have the Wyatts DBM on the rifle. The mags do allow you to load long. The feed lips are a bit sharp and it's easy to cut your fingertips trying to get that 10th round in the mag. My rifle does feed/function well with the Wyatts DBM.

Thanks for the great info on these mags. I have heard from others that they're somewhat difficult to load as well. I'm going to give them try just because I'll be able to run such a long COAL and still mag load the 80s and 90s. My stock is set up as a Remington BDL so it should just drop in.

Good luck with your new build.

 

[stuff]

Just started reloading the 75 ELD with a 7.7 twist and it works very well. I tried the 75 BTHP in the old original factory 9 twist barrel and they did not work at all.

The OAL of the 75 ELD is 1.120". Below is a pic of it next to one of my loaded rounds which is 2.467" OAL and sitting .020" off the lands. Fit perfect in the MDT .223 mags which allow up to 2.550". (sorry about the cat hair in the pic. They like to visit the gun room LOL)

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​ [IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i.imgur.com\/3GOPgX5.jpg?1"}[/IMG2]
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Thanks for the length info on the 75gr eld-m. It's interesting that it is longer than all the Berger bullets except the 90.
Nice shooting there, how does it do at distance?

 

[lte82]

When using the stability calculator for the eld or other plastic tipped bullets, you shouldn't include the plastic tip in the OAL.

Also, I shoot mostly 7.7 and 8 twist and up to 82 gr Bergers with great results. I've shot at least 5000 80+ gr bullets over the last few seasons and have never had any issues with either of those twists. If I were to shoot a 90 smk however, I would go 7 twist for sure.

 

[atxhorn4425]

When using the stability calculator for the eld or other plastic tipped bullets, you shouldn't include the plastic tip in the OAL.

Interesting. I assume that's because the polymer tip is much less dense than the actual bullet and using it in the calculator tells the calculator that the mass of the bullet is stretched out further than it really is? That makes sense to me, just never heard that before so want to make sure I understand what you're saying. The only twist rate calculator I've seen that mentions polymer tips is the JBM one.

 

[lte82]

https://www.google.com/url?sa=t&sou...CCSz_UBipR4nHthyA&sig2=yMxjuz-mQ33coXcg2aimzg

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[atxhorn4425]

https://www.google.com/url?sa=t&sou...CCSz_UBipR4nHthyA&sig2=yMxjuz-mQ33coXcg2aimzg

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Gracias

 

[CharlieNC]

Shooting the 75Amax from a 22in 8 twist I have consistent vertical performance at 1000yd, with similar drops as my 6.5x47. No problems with stability at 500ft elevation, no mag issues, just great shooting. If only the wind.........

 

[jsthntn247]

What freebore did you go with in your chamber? Smith has a wylde reamer but not sure if I wouldn't rather have a match reamer with around .075 freebore.

 

[lte82]

I'll simplify it.

If I were going to shoot 75-82gr *only* you could go with a longer freebore like what your gunsmith has, or stick with the wylde, I don't think you will notice a difference. If you want to shoot the 90 smk, I would go with a much longer freebore, something in the .100+ range, and you can still shoot the lighter gr bullets just fine. The AMU uses a freebore in the .09X range, and shoot 77 smk & 75 vld. Hope that helps.

 

[entropic86]

For 90 SMKs:

I originally purchased a .223 reamer with 0.148 of freebore. It was way too much to feed out of an accurate magazine (2.500 is about all the OAL you will get in the mag). I think the jump was well over .100 on a fresh barrel. I ended up using a 5.56 Nato reamer which has just over .100. My next barrel will have ~.080 of freebore for 90 SMKs.

 

[SEMO Shooter]

I talked to a reputable smith yesterday about Accurate mags. He modified the insert to accommodate longer COAL and is shooting 80 to 90 grain bullets in his. He will modify mine when I get them.

 

[Moose]

I run 8 twist for the 75 gr amax.Works out very nice.

 

[entropic86]

The mag modification is a given. If you want to load within .100" of the lands and have .148 freebore like the FTR guys run, you will have a much harder time modifying them to handle over 2.500". I'm still able to load 90s past the boattail junction with a NATO reamer and fit them in the mag.... the issue is they still have more jump than I want.

 

[lte82]

The mag modification is a given. If you want to load within .100" of the lands and have .148 freebore like the FTR guys run, you will have a much harder time modifying them to handle over 2.500". I'm still able to load 90s past the boattail junction with a NATO reamer and fit them in the mag.... the issue is they still have more jump than I want.

Are you shooting sierra or berger 90s?

 

[stuff]

If you were just going to shoot the 75-80gr bullets a Wylde chamber, FB of .0691", gives a COAL of about 2.45" with the 80gr Amax, still allowing the use of AI mags, 2.55".

The Criterion pre-fit barrels can be had in the .223 Rem Match chamber that has .100 FB. I've "heard" that it will put the 80s right at AI mag length, 2.55".

I can't recall where I got this info, it was ether here on the Hide or 6mmbr.

90's recipe

1. PT&G ISSF reamer with .169 FB
2. See #1 above, don't go further with less freebore or you will break something.
3. 1:7 twist barrel (mine is a 28" 3 groove Lilja, though just ordered a new 30" Brux)
4. 90 VLDs jam .015
5. Brass of your choice, I use LC and Federal
6. 24.5 ±.2 gr of Varget (others work, including H4895)
7. I shoot Tula 556M primers, but you can't get them any more (Russia sanctions)
8. Do your load work and get it dialed.

This will be a single load situation with a COAL over 2.65", unless you used the Waytts magazine with a max COAL of 2.850".

 

[Greg Langelius *]

I have successfully shot (they arrived supersonic, accurate, and not keyholing) the HDY 75gr HPBT Match in 600yd competition in a 24" 1:9" Savage, and a 24" 1:8" Stag Super Varminter. That bullet was loaded at magazine length (2.255" OAL) in unprepped Winchester brass, with the CCI BR-4 and 24.4gr of Varget.

This may seem like a wimpy load compared to some of the ones posted here, but in fact, it's only .6gr under max for this weight bullet per Hodgdon and .2gr under max per Horandy. I try not to shoot max or over; it's a brass/bore life thing with me.

 

[jlow]

I have been shooting the Berger 80.5 gr Full Bore out of my 23.75" long Tikka T3x .223 Varmint with a 1:8 twist factory barrel up to 600 yards with no problem. Very accurate rifle and bullet.