90 Gr. SMK 223

Diver

Diver

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I am planing to get my first custom rifle built in the very near future. A 223 paper puncher for shooting up to 600 Yds for now and hopefully up to 1K once my shooting and wind doping skills improve. I was planning to get a 28" 1 in 8" twist barrel to shoot 55 - 80 Gr. bullets. However, after looking through Sierra's web site, I noticed that they now have a 90 Gr. bullet. This bullet requires a 1 in 6.5" twist rate. This bullet has a BC of .504 compared to .420 for the 80 Gr. SMK

Are there any disadvantages in going to a faster twist barrel?
What would be the lightest bullet I could shoot with such a rifle?
Are there any other things I should consider?

Any info would be appreciated as this is going to be a major investment on my part.

Thanks,
 
If you're already going to the expense of rebarreling, I would strongly argue don't go for .223. There are much better choices for what you want to do, look at .260 Rem, .243, 6mm BR (ideal for what you have in mind).

With a 1-6.5" twist I'd bet bullets would start tearing apart around the 50gr range. So basically you can still shoot a huge variety, 70gr+ will shoot very well. Remember that a twist rate has a certain amount of "adjustment" range, that is the velocity at which you launch the bullet. Higher velocity=faster spin and vice versa. There is a small window here, and you can tune most reasonable loads well if you are an interested handloader. A faster twist will wear slightly faster, but this is offset by the lower velocity of heavy bullets, so the difference isn't huge.

Last question; I'll say it again, take a hard look at 6mmBR, it's the leader in the type of shooting you mentioned, and shoot 105-107 gr 6mm bullets with BC's over .500 (customs go up to and past .600) with long barrel life and extreme accuracy. It has a .473" bolt face, so all you need to do is rebarrel a .308 based short action.
 
The .223 is a good choice for a person learning the game of long range shooting. Something with a 1:8 twist will shoot 80 gr bullets out to 1000 yards. The .223 has no recoil to talk about, and is cheap to load.
I don't know if the 90 gr SMK is the magic bullet over an 80 gr SMK, 75 gr A-Max or 80. gr Nosler.
If you go with a .223 have a .223 Wylde chamber put in. It was deinged to shoot the 69 grain bullets, but also works for 80 gr.
 
Ardent said:
If you're already going to the expense of rebarreling, I would strongly argue don't go for .223. There are much better choices for what you want to do, look at .260 Rem, .243, 6mm BR (ideal for what you have in mind).
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This rifle is going to be built from scratch. I am also set up for reloading. I would therefore have options as far as the caliber I use.

I currently own a Rem model 700 LTR 308 which I could use for F class. I am thinking of shooting competetively but not necessarily benchrest. I love shooting prone. I have never shot competitively and I am unsure what calibers are used or classes I could shoot in.

The main reason I was looking at a 223 is that I would be able to set up at locations other than the range in order to shoot as long as I have my varmint licence. It would be somewhat of an all around rifle.

I checked out the 6MM BR web site. I am now rethinking my options. I think the 6mm BR with the no neck turn chamber could be a very intersting solution for me. The only downside would be that I could only use it at the range.

Any other comments or suggestions would be appreciated.

Thanks,
 
Diver,
If you are thinking about prone target rifle shooting, iron sights and all. .308 and .223 are allowed.
The .308 only is used for international comp. ie Bisley and Palma, and is the caliber you have to use to qualify.
Build yourself a .223 and learn the game.
A .223 with 80 gr bullets is right up there with a .308 with 155 gr bullets as far as reading the wind, and elevation come-ups from 100 to 1000 yards.
 
Incidentally, there seems to be a trend among .223 LR target shooters to go with longer barrels - 30-32". I don't know that I would build a rifle specifically intended for the 90SMK, or JLK. There are a number of fine bullets 69 gr and up, Sierras, Noslers, Bergers, Hornadys. By all means, get in contact with the RNBRA (can be linked through www.dcra.ca), and have a go at some F Class shooting with your .308. Then decide if you want to invest in the new rifle. While there are shooters who do very well indeed with .223 at long range, if you are going to build a dedicated open F Class rifle, there are probably better cartridges than .223.
 
I would highly recommend the 6mm BR chamber cut with a reamer for using Lapua brass with no neck turning.

You will be amazed at the performance that cartridge. It is an excellent varmint round as well as being extremely accurate.
 
Diver said:
In New-Brunswick varmint rifles are .23 or less in diameter. See page 8 of the linked document bellow.

http://www.gnb.ca/0078/fw/huntsum.pdf
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Well that is the stupidest thing I have ever read... a backward law... I guess the intent may to make poachers use smaller calibers.....:D

Out in the west they place minimum restrictions on game animals but we can hunt varmints with any caliber we wish.....
 
If you decide to build a 22cf specifically to use the 75 and heavier bullets, especially the 90gr, I would go with a bigger case. Velocities with that 90gr bullet and a 223 will be around 2400 to 2500fps. Not very impressive when a 6BR can launch a higher bc bullet over 3000fps.

Like most are saying, for match shooting, the 6br and 87gr to 107gr bullets simply kick a 223 load. However, a 22.250 or AI, even a 22BR/PPC, in a very fast twist and those 90grMK might make a sound argument.

One other thing, any idea where you are going to get your 90gr MK's?????

Most of my design choices revolve around the components I can readily and affordably access.

Jerry
 
mysticplayer said:
If you decide to build a 22cf specifically to use the 75 and heavier bullets, especially the 90gr, I would go with a bigger case. Velocities with that 90gr bullet and a 223 will be around 2400 to 2500fps. Not very impressive when a 6BR can launch a higher bc bullet over 3000fps.
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Thanks for pointing out the velocity aspect. I never realy thought of it. I guess I am back to considering a 223 1 in 8" twist for bullets up to 80 GR or a 6mm BR 6mm chamber cut with a reamer for using Lapua brass with no neck turning 1 in 8" for shooting 107 Gr bullets.

Is there a big reloading cost differece between these 2?

I am trying to make an educated decision. I appreciate all the responses.

Thanks,
 
Reloading costs will be very similar. In fact, I think the 90gr 22cal would be expensive due to availability. Also, ballistics are not particularly exciting given the speciality of the set up and costs. Initial brass cost for the 6BR is higher but brass life is usually very long.

Curious why you don't want to neck turn? A very simple operation and does open some options in tuning and reamers (ultimately the chamber cut is based on the reamers available unless you want to buy another reamer).

For the distances you initially plan to shoot, the 75gr Amax/77gr Nosler/MK in 223, 87gr Vmax in the 6BR would be ideal. If you go to the km, then play with heavier bullets to see which works best in your rifle, conditions, and your style of shooting.

As always, there are trade offs so really testing at distance is the only way to know the right combo. The actual best combo may not be what you had initially thought about.

New bullets also change what is the best set up. Good luck.

Jerry
 
Diver- Where in NB are you? There are a few of us who shoot .223 in matches sponsored by the RNBRA, so you won't be alone. Drop me an email and we might be able to get together.

matt
 
more nb specific .223 info

I would side with the others if you lived anywhere else, but .223 makes about the most sense if you want to shoot very much here in NB. You already know about the laws surrounding varmint hunting. The other thing to consider is the RNBRA sponsors lots of long range matches during from May to Sept. Equipment classes include target rifle, F Class, and MTR. F Class is wide open, but TR and MTR is restricted to .308 shooting 175 gr. or lower, or .223 shooting 80 gr. or lower. I shoot a .308 most of the time, but there are very few places where you can shoot anything larger than .22 centerfire outside of bear or dear season. Get yourself a good fast twist .223 and a varmint license, and you can shoot 75 gr. Amax, or 80 gr. Sierras, still be competative and shoot where ever, when ever. You will give up a little bit at 800 and 900 meter stages, but the majority of the matches are at 300, 500 and 600 meters, where the .223 can definatly hold its own. The nice thing is you can pick up one of the 1-9 twist factory rifles and see for yourself. Then rebarrel as nesessary. Rem 700 Police, or a Savage VLP would be my suggestions.They may or may not stabilize the 80 Sierra, but 75 and 77s are a good bet to shoot. Shoot it for a while and then take it to Gordon Whitman at Blue Mountain Sports for a 1-8 Walther tube when you have the scratch. Another good consideration would be a Tika- they come with a 1-8 twist, which will definatly stabilize up to a 80 gr. Drop me a PM and we can hook up to shoot a match or bust some clays. You can check out my 1-9 .223 and decide for yourself.
 
I'd like to thank everyone for their input. After reading all your posts especially the one from Mpwolf and talking to my gunsmith I decided to go with a custom 223. This will be my first custom rifle. :D


Here are the reasons why:

I can use a 223 year round at locations other than the range due to New-Brunswick varmint laws.
Many of the matches in New Brunswick are limited to 308 and 223 and are mostly 600m and less.
My local range is 600 Yds
223 is cheap to reload.
Recoil is minimal.
A 223 barrel usually lasts a long time.
I already own a Rem 700 in 308 and if I want something different, I can always rebarrel it to another caliber later on.
If I lived in a different province, my choice would probably be different.


In case some of you are curious here are the rifle details:

Blueprinted Rem 700 Action
Lothar Walther 28" Stainless 1 in 8" twist barrel
Boyds laminate target varmint stock.
Aftermarket trigger set to 8 oz.
High speed firing pin.
Aftermarket recoil lug.
Gunsimth is Gordon Whitman at Blue Mountain Sports
I also ordered a Redding Competition Bushing neck die set. This will give me the option of neck turning my brass.

When I receive the rifle I plan to work up my loads using Lapua Brass, Remington Benchrest Primers, Varget and 80Gr SMK.
I will try to post a range report once my load development is done.


Thanks again for all the info.

Mark
 
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