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Loading advice for rifle


Happy plinker

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Hello Guys,

I was wondering if anyone can direct me to reloading data for my rifle. It is 223/5.56 straight pull with a short barrel with a 1 in 8 twist.

 

The barrel is the shortest that is uk legal. Factory ammunition has been terrible and is never consistent. Any advice would be great.

 

Thanks

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That’s a relatively ‘fast-ish’ twist. 1-8” should be good stabilising bullets up around the 77gn mark. My own 1-7” twist (.223AI) is intended for the 77-88gn bullets.

Personally I would look at load data for the the 69gn-77gn bullet weights.

The thing that is likely to scuppa you is the right powder & velocity. With a heavy/long bullet, you really want to use the mid-slower burning powders to generate enough pressure and velocity over the entire length of the barrel to push the heavies at any meaningful speed. Like N140/RS52 etc.

By way of comparison, my .223AI with 1-7”  26” long barrel is throwing a 77gn SMK out around 2980fps with N140.

However, with a very short barrel (how short is it btw??) the mid to slow powders won’t do well because they simply can’t produce enough decent pressure/velocity before the bullet exits the muzzle. You’re therefore likely to see very low speeds - possibly around 2000-2200fps with my same load above.

So you have 4 choices I see;

1. Go for the heavier bullets (per what your barrel twist is geared for) but try some faster burning powders to maximise pressure to barrel length. But be careful as you’re likely to run into some very high pressures, very quickly.

2. use the heavier bullets but use the normal go-to powders (eg N140) and accept velocity is likely to be very low.

3. Go lighter bullets (say 55gn-69gn) with normal go-to powders (eg N140, RS52 etc) but know that your barrel may not like these lighter bullets as much as the heavier type. 

4. If 1, 2 or 3 don’t work, consider replacing the barrel with one that’s a bit longer to maximise the pressure/velocity 

It’s worth taking a look at the .223 reloading page on Accurate Shooter. Some good advice and useful starting points for load development.

https://www.6mmbr.com/223Rem.html

As ever, all just an opinion.

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I have a Remington 700, .223 (in an MDT stock) with a 20 inch barrel and I use the following (works in my rifle, don't now about yours):

Lapua brass;

CCI 400 primer;

69gr Sierra Matchking bullet;

25grains of Vihtavuori N140;

The above gives an average of 2811 ft/s

You could start the load development from here:

Rifle reloading data | Handloading | Rifle calibers | Centerfire Rifle bullets | Reload your own ammo - Vihtavuori

For comparison, using the above components but with different power weights, I obtained the following velocity on my chronograph:

24ge=2683ft's

24.5gr=2758ft/s

25.5=2847ft/s

I have shot this rifle/load out to 600 yards.

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On 11/17/2021 at 1:48 PM, Happy plinker said:

Hello Guys,

I was wondering if anyone can direct me to reloading data for my rifle. It is 223/5.56 straight pull with a short barrel with a 1 in 8 twist.

 

The barrel is the shortest that is uk legal. Factory ammunition has been terrible and is never consistent. Any advice would be great.

 

Thanks

1 in 8 needs a heavier bullet up to 80 gn,  easy route as a test, go and buy some GGG 69gn match (which uses the Sierra MK 69 gn bullet) from the NRA to try, they do it in boxes of 20, that is an excellent  budget (about £18 per 20) factory ammo in the right load ball park, if it works satisfactorily I can give you a guide towards a load that will work even better, or you can stick with that, if it doesn't work, I suspect then its maybe the rifle is not the ideal choice for precision shooting.

My criteria is tight accuracy not just speed for the sake of it, I shoot a precision match course (ISSF 300 mt) with a 1 in 8 twist .223, with a 25" Bartlein barrel on a Barnard P action, I tried the GGG, it was a very tight group at 300 mt, but a tad slow, so not good in wind (at 300), if you are plinking, and the rifle is not exactly match grade, I think the GG 69gn Match should out shoot your Rifle.

Best of luck

Have Fun

Robin

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I shoot a 14.5", 1-8 twist AR-15 and I get half MOA with 50 and 55 grain Noslers. I have a 18" Ruger bolt gun that loves Fiocchi 50 grain factory ammo and it is also a 1-8 twist. The twist rate is probably not the issue. The OPs initial post was written as if to limit the information: What rifle? What barrel length? What factory ammo? And lastly, what is considered 'terrible' accuracy?

Frankly, JCS' remark was not far away from what I was thinking. If you shoot a variety of factory 223 ammo and get terrible accuracy, the rifle might be suspect. Factory 223 is generally good in most rifles. JMHO ~Andrew

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Hmm … freedom bucket doesn’t sound like match quality fodder to me but I am happy to be corrected. I would try some decent 55g , 69 grain and 75 grain bullets and see what the rifle likes. Just because it has a fast twist barrel doesn’t mean it won’t shoot lighter bullet weights

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What does the OP call "terrible accuracy" ?   What groupings are being achieved with the bargain-bucket rounds?

There's no reason why a fast-twist barrel should fail to shoot a lighter bullet accurately,  maybe a slower MV than desirable but extra spin isn't going to cause stability issues.

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53 minutes ago, Popsbengo said:

There's no reason why a fast-twist barrel should fail to shoot a lighter bullet accurately,  maybe a slower MV than desirable but extra spin isn't going to cause stability issues.

Well, there's a couple of reasons I can think of off my head.

The first is that a rapid expansion vermin (varmit/varmint) type with a thin jacket fired at high speed and high spin may break up, or fly erratically. Not experienced it myself, so can't say for sure of its validity, but it makes sense especially if the jacket is partially cut-through by the rifling.

The second is a bit more complex. Just because something is gyroscopically stable, doesn't mean it's dynamically stable. You have to remember that the gyroscopic and dynamic stability both change as the projectile moves downrange. This as the projectile's velocity and spin are both changing, as is its orientation in relation to the direction of flight.

I have a basic understanding, but don't profess to have full understanding of this (i.e. the interaction of the factors that result in dynamically stable, and then not stable bullet). It's something I need to teach myself and I've got plenty of books on ballistics to read. Unfortunately I need time to do this and a lot of peace and quite. As such I've just not got round to doing it.

Anyway, some bumph about the subject online can be found at the links below.

http://ffden-2.phys.uaf.edu/212fall2001_Web_projects/Isaac Rowland/Ballistics/Bulletflight/stab.htm#Dynamic_stability

http://ffden-2.phys.uaf.edu/212fall2001_Web_projects/Isaac Rowland/Ballistics/Bulletflight/dynacond.htm

As mentioned in the first link, there's a projectile's (bullet's) tractability too. This most certainly could be a problem with long range rifle shooting. Not really the same, but 155 mm artillery projectiles can suffer from this problem when fired at very high elevations. Essentially they get near the apex and, as their velocity has decayed to practically zilch but they spin is still high, lets say after this point they don't tend to follow the expected trajectory!

 

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53 minutes ago, BlueBoy69 said:

Well, there's a couple of reasons I can think of off my head.

The first is that a rapid expansion vermin (varmit/varmint) type with a thin jacket fired at high speed and high spin may break up, or fly erratically. Not experienced it myself, so can't say for sure of its validity, but it makes sense especially if the jacket is partially cut-through by the rifling.

The second is a bit more complex. Just because something is gyroscopically stable, doesn't mean it's dynamically stable. You have to remember that the gyroscopic and dynamic stability both change as the projectile moves downrange. This as the projectile's velocity and spin are both changing, as is its orientation in relation to the direction of flight.

I have a basic understanding, but don't profess to have full understanding of this (i.e. the interaction of the factors that result in dynamically stable, and then not stable bullet). It's something I need to teach myself and I've got plenty of books on ballistics to read. Unfortunately I need time to do this and a lot of peace and quite. As such I've just not got round to doing it.

Anyway, some bumph about the subject online can be found at the links below.

http://ffden-2.phys.uaf.edu/212fall2001_Web_projects/Isaac Rowland/Ballistics/Bulletflight/stab.htm#Dynamic_stability

http://ffden-2.phys.uaf.edu/212fall2001_Web_projects/Isaac Rowland/Ballistics/Bulletflight/dynacond.htm

As mentioned in the first link, there's a projectile's (bullet's) tractability too. This most certainly could be a problem with long range rifle shooting. Not really the same, but 155 mm artillery projectiles can suffer from this problem when fired at very high elevations. Essentially they get near the apex and, as their velocity has decayed to practically zilch but they spin is still high, lets say after this point they don't tend to follow the expected trajectory!

 

I've 'seen' jackets fail on old .303 at Kingsbury - very strange to observe.  I discounted this possibility as it's bargain bucket plinking ammo rather than expanding etc.  My thoughts were very much related to the OP rather than some more theoretical appreciation.  I have read a bit on ballistics but I'll defer to your knowledge as you certainly have wider experience.

I ran some  numbers through a couple of stability calculators based on a few well known bullet designs, the difference between a 1:14, 1:10 & 1:8 twist just got more stable (I thought this validated my understanding).

Not wanting to hijack the post but am I right to think a bullet doesn't fly nose first (like an arrow)over the whole trajectory, rather as it starts to descend along trajectory the gyro forces tend to keep it nose-up?

 

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On 11/21/2021 at 1:48 PM, Popsbengo said:

I've 'seen' jackets fail on old .303 at Kingsbury - very strange to observe.  I discounted this possibility as it's bargain bucket plinking ammo rather than expanding etc.  My thoughts were very much related to the OP rather than some more theoretical appreciation.  I have read a bit on ballistics but I'll defer to your knowledge as you certainly have wider experience.

I ran some  numbers through a couple of stability calculators based on a few well known bullet designs, the difference between a 1:14, 1:10 & 1:8 twist just got more stable (I thought this validated my understanding).

Not wanting to hijack the post but am I right to think a bullet doesn't fly nose first (like an arrow)over the whole trajectory, rather as it starts to descend along trajectory the gyro forces tend to keep it nose-up?

 

As to loading advice for this short 223 Remington rifle, what exactly is the barrel length? Other than powder burn inefficiencies, what's the problem? A shorter barrel should be stiffer, but it will oscillate at a higher frequency, which I guess may make round tuning harder? You should be able to just take normal 223 load data for AR-15 style firearms, albeit the velocity will be lower. If you want better ballistic efficiency, use the load data given, but choose the faster burning powders.

I've seen 'jacket' separation/expansion many times on plated bullets, for example with H&N and the South African Frontier CMJ (frontierbullets.co.za) bullets (even though the latter says it never happens). You end up with little rectangular cuts in the paper target in the areas of the 'jacket' that has failed. Not seen it on true jacketed bullets, but I'm sure I will. (Maybe I need to put some .22 Hornet light-jacket bullets in my 22 PPC and fire them at silly speeds?)

Yeah, of the online calculators I've seen, all just calculate gyroscopic stability, not dynamic stability or the bullet's tractability. Hence most are just guides, and real world shooting is required.

The bullets pitch and yaw downrange depend on its gyroscopic stability, dynamic stability and the tractability, along with any initial yaw (see starred later comment), metrological conditions, etc., etc... If over gyroscopically stabilised near the end of the trajectory when its coming down towards the target, then yes, it can can end up flying in a non optimal orientation. The drag also affects the stability and this the problem people get when their bullets are in the transonic region of flight downrange, as the drag commonly jumps to a high level as the local speed of sound is reached.

If you want to know if the bullet will follow the trajectory, you'd have to plug the data into the tractability condition equation (link and below)... good luck!

It's all a bit complicated to be honest. I say just make sure it's at least gyroscopically stable and then go shoot a few rounds and see what happens!

*** The factors such as bullet jump, throat conditions, round concentricity, crown condition and barrel movement are not the only ones that can affect initial bullet yaw. Charge ullage in combination with the ignition device (primer) can also cause a bullet to be driven into the rifling with a small initial yaw. You may not believe it, but it's been studied and proved to occur (if you want to believe the papers on it).

The tractability condition.jpg

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2 hours ago, Happy plinker said:

Average of 200yds max 500yds paper targets

I'd be looking at slightly heavier target bullets, 69gr SMK or similar and heavier, but with your short barrel which I assume is 12" from your description I don't know which powder to suggest.  Might be worth downloading gordons reloading tool and have a play with that

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Hi its about 12 inches but I'll take a tape to it tomorrow and confirm this. The groupage with freedom bucket was about the size of my hand at 100yds with a bipod and bag. It was never the same poi.

I'll try heavier factory ammunition and ultimately look to home load to be more specific 

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Attached is a QuickLOAD export Excel file that lists a range of powders 'supposedly' suitable for use with the 223 Remington when loaded with a 77 grain Sierra Match King to a COAL of 2.260", and fired from a 12" barrelled firearm. The maximum chamber pressure is as per CIP (4,300 bar/62,366 PSI). I can do different pressure levels, bullets, COALs, etc...

Be aware it's just a guide, but it does give you an idea, if you reload, what powders will likely give you the best burn percentage in your short barrel and potentially the highest muzzle velocity.

I'm not sure if you can do these power range analysis with Gordon's Reloading Tool, as I've only used it a bit and then only when it was non-registered access.

77 gr Sierra HPBT Match King With 12 Inch Barrel.xlsx

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The easy way?

Just buy some GGG 69gn (Sierra bullet) from the NRA, its cheap, and shoots well in a decent 1 in 8 barrel/action  combo, GGG also make a 77gn (also Sierra bullet), similar price, (but not available from the NRA), if they shoot well, to your satisfaction you have a route, as they can be easily mirrored in a load.

If not, its almost certainly the rifle quality, which to be honest sounds like its not exactly a silk purse.

Or you could play for ever with opinions on loads and intense technicalities, and still never get further than you are now!

Have Fun

Robin

 

 

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1 minute ago, RobinC said:

The easy way?

Just buy some GGG 69gn (Sierra bullet) from the NRA, its cheap, and shoots well in a decent 1 in 8 barrel/action  combo, GGG also make a 77gn (also Sierra bullet), similar price, (but not available from the NRA), if they shoot well, to your satisfaction you have a route, as they can be easily mirrored in a load.

If not, its almost certainly the rifle quality, which to be honest sounds like its not exactly a silk purse.

Or you could play for ever with opinions on loads and intense technicalities, and still never get further than you are now!

Have Fun

Robin

 

 

sound advice.  From what you say about group size I suspect it's a pretty poor tool.

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