Sierra Bullets

[rebs]

I called Sierra talk to a tech at 1-800-8799 and asked about the 77 grain matchking bullet not being listed in the bolt action section of their manual. The tech guy said just use the AR 15 section for that bullet, huh ? I questioned what he said and he replied that you can use the AR 15 section for all their bullets in a 223 bolt action rifle just don't start at maximum loads. Can this be right since their AR 15 section says 223 Rem and does not say 5.56 ?
This just doesn't sound right to me. What is you guys opinions ?

[RC20]

section says 222 Rem and does not say 5.56 ?

Typo? 223?

223 and 5.56 are the same. Some very miner chamber difference in 5.56 but not an issue in a rifle.

You can go higher in a bolt possibly as you can see the pressure signs easier and feel a sticky bolt, an AR might just bind.

Start low and work up. Cross check with the 80 gr that is listed in the book (app is updated)

[greaseswabber]

I just looked at the new Sierra app. It has the 77 grn hpbt in both the ar-15 and bolt gun sections for 223 rem.

The data is not identical. Different powders are listed. Varget is shown in both, but with different loads. Max of 23.9 in ar-15, 22.6 in bolt gun.

[P-990]

The AR-15 section should be listed as .223 Remington. And it will be safe in a .223 Remington bolt action because SAAMI max pressure is the same no matter what action you're using. I use the same loads in both of my AR-15s and my CZ527 bolt action. (However I wouldn't use my heavy bullet loads in a single-shot like a TC or an H&R. They're almost guaranteed to give sticky extraction in one of those.)

More importantly, what powder and cases are you using?

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[rebs]

I am using LC brass and REloader 15 and Varget powder
where can I get the new sierra app ?

[greaseswabber]

I have an Android phone. So I got it from the Play store. I think Sierra just released the iPhone version too. So check the app store of you are an apple person.

[cw308]

77 gr bullets for ar15 maybe something to do with twists . I gave my Colt HBar 20" 223 lower with a 5.56 1/7 twist ,to my Son-in-law , your bolt action with a 1/12 twist , that bullet my be alittle too heavy . AR's may require a heavier starting load do to being a semi . Bolt action can use a lower starting load . I'm just giving you reasons why they said the 77 was for the AR .1/7 1/9 twist can't see and reason why they wouldn't be for a bolt . Could try a lighter bullet , haven't loaded 223 in awhile 62 or 69 grain , there is a formula for twist and bullet weight you can look up , may be helpful

[TX Nimrod]

The chamber dimensions for the 5.56 are “tighter” than for the .233, so loads designed for the 5.56 will be safe in the “looser” .223 chamber. But many/most of the .223 bolt rifles around have a twist too slow for long bullets like the 77-grain.

My 1980s-vintage AR runs just fine on reduced loads, at least down to a bit below starting loads. But its slow 1:12” twist keyholes with long boat-tailed bullets. It does shoot very well with the 70-grain Speer SP at 2650 fps.

.

[RC20]

rebs:

You don't need the app. You have the AR data and you can use the low end of the 80 gr bullet data in the bolt section.

You are going to start lower and work up, cross reference both and see but without looking at the book mid would work fine.

The 5.56 is no dimensionaly larger, the lead is longer

https://www.thetruthaboutguns.com/20...r/5-56-vs-223/

[P-990]

Rebs, you can also go right to Alliant's web page and pull up the data for RL15 in their guide as well. I just checked, they do have a listing for the 77gr Sierra Matchking under their .223 Remington data.

My Nosler manual only lists the heavy bullet loads (69, 77 and 80gr) in 5.56 NATO data with a 20" barrel. It tracks with what I loaded for years for Highpower shooting with an AR15 using those bullet weights. Which matches pretty closely to what Alliant, Lyman and Hodgdon have listed.

(Obviously depending on powder. I've used H4895, Hodgdon Varget and Alliant RL15, depending on what is available. I also used Nosler Custom Competition and Sierra Matchking bullets pretty much interchangeably.)

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[cw308]

First time shooting AR's was in VN the 16's back then were 1/14 twist with a 55 FMJ wounds were horrific didn't understand why , didn't know anything about twist rates , later on changes were made with forward assist and twist 1/12 also handled tracers much better . Faster twist rates handle heavier bullets mush better . The bullet should match the twist rate . 1/12 twist will give longer barrel life and also with the right bullet be plenty at 300+ yards . If wanting to go long 6.5 CM is something to look into .

[rebs]

My rifle is a Tikka 24" heavy barrel in 223 with 1/8 twist

[cw308]

Sorry rebs , had you confused with another post . Your fine with any weight . Be Well

Chris

[Jim Watson]

As I recall, the 77 gr Sierra is a magazine length bullet, originally designed for High Power matches with rapid fire at 300 yards. The expectation is that you will use a heavier bullet loaded long and chambered singly for slow fire at 600 yards.

Plenty of load data around. When working with the 90 gr Sierra (6.5 twist) I found that the Sierra maximum load shot well with no "pressure signs" but that it was the maximum because the bullet would not stand any higher velocity/faster spin. I loaded Bergers hotter.

[briandg]

This may have been mentioned. The 77 grain will require a very specific twist rate that may put the lower weight bullets out of usefulness. Bot rifles are going to be made to , utilize mostly normal weights and velocities. and seriously, I can't imagine that many people would want to use it. A bolt may not function well with the heavy, long bullet that could be used in an AR with an alternative barrel.

[P-990]

Originally Posted by briandg

This may have been mentioned. The 77 grain will require a very specific twist rate that may put the lower weight bullets out of usefulness. Bot rifles are going to be made to , utilize mostly normal weights and velocities. and seriously, I can't imagine that many people would want to use it. A bolt may not function well with the heavy, long bullet that could be used in an AR with an alternative barrel.

The current trend seems to be to equip even bolt-action .223 Remington rifles with fast-twist barrels (1-9" to 1-8" typically) to allow the use of the heavy, magazine-length bullets available. rebs' Tikka with a 1-8" twist barrel can stabilize up to an 80gr lead-core, HPBT bullet easily. Of course, the long 80gr bullets are going to be a single-shot only proposition, I doubt the magazine box is long enough to feed them.

There shouldn't be any functional issues with the heavier bullets, regardless of action type. A magazine-length round is a magazine-length round, it really doesn't matter what action it's being fed through. To whit, my earlier comment about using the same exact magazine-length reloads in 2 different AR-15s and a CZ527 bolt action. (If you're curious, normally it's a 69gr Nosler Custom Competition seated to 2.25" OAL over a heavy charge of Varget in Lake City cases. But I do have some 75gr Hornady HPBTs loaded to 2.25" OAL over a MAX charge of Varget in Lake City cases that shoots equally well in my 16" 1-7" twist Colt 6920 and the 20", 1-9" twist CZ527 barrel.) It also isn't guaranteed that the lighter .224" bullets, say 60gr and under, won't shoot well in a faster twist barrel either. My match barrels have all shot great with 52gr HPBTs over ball powder, and my CZ seems to like 55gr Nosler Varmageddon bullets over H4895.

rebs, you're not reinventing the wheel. What you're loading is what literally thousands of Highpower shooters have loaded 100s of thousands of rounds for, and used in bolt action or AR-15 match rifles. The 77gr bullet is a good one out to 300 yards, and is OK for gunning to 600 yards so long as the wind conditions are calm.

Jim Watson, I have to admit, you're the first person I've heard or seen say the Sierra bullets couldn't take higher speeds/spin rates. I have "seen" (witnessed?) 2 .308 shooters "lose" bullets between the muzzle and the target at 600 yards, 1 of which I know for sure was using Hornady match bullets. I was behind them on the line watching through my spotting scope when it happened. And I was in the pits one day when a shooter had at least one 75gr Hornady HPBT come apart between muzzle and target. He had 9 good 10/X hits and we found jacket fragments of round #10 on the target face 2 points to the right.

[RC20]

My rifle is a Tikka 24" heavy barrel in 223 with 1/8 twist

Nice

That said, this is not super precision and the loads can be done exacly as noted in startring low and working up

Your book shows two starting points.

The AR-15 with the 77 and the Bolt with 80.

Cross compare the loads with same powder and you can find a good startling point that does not have to be the very lowest (I often do start at mid) and go from there.

Usually new powder I start low as I can find a node there that allows a 100 yard plinker type, nicer shooting and saves on barrels and shooter both.

[cw308]

I never liked the need for speed , I'm sure you could find a reload at a lesser charge or seating depth to shoot just as accurate . Friends of mine shoot very hot , that's why I keep a stuck case remover in my range . Every season two or three times I hear , Chris can I borrow your case remover . We all get a kick out of it but they still love the speed . I never used the tool but it's good to have , they work great and easy without causing any chamber scratches . If your into speed look into one . Caliber specific , I only shoot 308 .

I only shoot at 200 yards , maximum distance for the outdoor ranges in my area . I reload below the starting load for the bullet and powder used . Sierra 168ge HBBT MK bullet on top of 40.84 grains of IMR 4064 . Granted if I could shoot at longer ranges I would goose up the load more but would get there the same way I did for the 200 yard range .

Even at 200 yards my friends are still blowing the heads off their cases and leaving the case body stuck in the chamber . I'm with them as far as accuracy . Need for speed at 200 yards with a 308 for target shooting only , not for me . 223 are lighter but if shooting at 200 yards , I would do the same even 300 if I could .

Chris

[T. O'Heir]

The type of action used is not a criteria for reloading.
"...says 223 Rem and does not say 5.56?..." That's because they're the same thing.

[Jim Watson]

Jim Watson, I have to admit, you're the first person I've heard or seen say the Sierra bullets couldn't take higher speeds/spin rates.

Well, it was an extreme case.
I bought a 28" 6.5 twist .223 barrel for 90 gr SMK, trying to make a FTR out of it. Sierra max loads were not enough to stay supersonic to 1000yds; overloads delivered the occasional missing bullet. I finally caught one on paper at 100. The bullet was BENT, not fragmented, a "C" shaped hole in target and backer.

75 Amax was worse in that fast twist, my spotter said he could see silver trails in the sun when one broke up.

Both were accurate, fine up to 600 yd at book loads.

Berger and especially JLK VLDs would stand the gaff of heavy loads and shoot well to 1000.

BC claimed comparable to 175 gr .308 but I don't think they shot as close to the wind. And hard for the pit to find teeny holes.

[Unclenick]

Yes and no. The case dimensions for 223 and 5.56 NATO are the same. Contrary to what TX Nimrod said, the 5.56 chambers are looser and have longer freebore than the standard SAAMI chamber. Then there are even tighter "Match" chambers and even looser general purpose chambers. This drawing shows the dimensions of 8 different ones.

The .223 Remington has the same specs as M193 that it copied. Both have chamber pressure MAP of 52,000 CUP, which measures about 55,000 psi on the SAAMI type conformal transducer. But M193 was never approved as a NATO cartridge. For 5.56 NATO, the various European experts felt penetration had to improved, so they came up with the Belgian SS109 (M855 is the U.S. copy), which runs at 6% higher peak pressure (55,000 CUP or 58,200 psi on the conformal transducer and almost 62,400 psi on the NATO channel transducer). More recently, to go to a lead-free cartridge with sold copper base and bearing surface, the M855A1 EPR ammunition has been developed that runs at still higher pressure of 62,000 psi by conformal transducer (about 58,600 CUP and about 66,400 on an EPVAT channel transducer, if all readings remained proportional, though they probably won't, quite). This is almost 13% more pressure than the original M193 and SAAMI 223 spec. This higher real pressure resulted from wanting to use a faster powder to cut down muzzle flash from the shorter M4 barrels and to increase velocity and use solid copper bullet bases (steel tip) all at the same time. There have been complaints about bore errosion from these rounds as a result. The AR-based guns all shoot them.

A SAAMI standard pressure is supposed to be safe in all guns ever made for the round, as long as they are in good condition. That does not mean guns don't exist that can handle much higher pressures. Most can. In the case of the Tikka, if the same action is chambered in the larger diameter, higher pressure rounds, it is more than beefy enough to handle even the M855A1 EPR ammunition. You just have to accept higher throat wear from running higher pressures. Jumping between Hornady loads for 223 and 5.56 is not going to hurt it. The one and only thing you really need to be concerned with is the longer throat in the 5.56 NATO chamber allows it to accept some blunt bullets seated longer without interference. This is for specialty loads, as I understand it, though I've never actually seen a military load that a SAAMI chamber couldn't handle. So it's just something to keep in mind if you buy surplus ammo for the SAAMI chamber. Check the fit of what you've got.

As to the 77-grain match bullets, they were used in M262 ammunition for the Squad Designated Marksman program and they work fine out of anything with an 8½" or faster twist, and with enough velocity they will shoot out of many 9" twist guns, especially at higher altitudes (but some 9" twist guns have issues with it). You won't. Keep its design purpose in mind, though. It doesn't have the best BC. It was, as previously mentioned, originally a design expedient for shooting 300-yard rapid fire, meaning it had to be blunt enough in shape to be loaded to fit in the magazine. That bluntness cost it BC, but it does its job well, and many folks shoot it from 600, too. That's why the SDM program wanted to be able to do with it and it works. You just have a bit more wind correction to make than with the 80 and 90-grain bullets.

[P-990]

Originally Posted by Jim Watson

Well, it was an extreme case.
I bought a 28" 6.5 twist .223 barrel for 90 gr SMK, trying to make a FTR out of it. Sierra max loads were not enough to stay supersonic to 1000yds; overloads delivered the occasional missing bullet. I finally caught one on paper at 100. The bullet was BENT, not fragmented, a "C" shaped hole in target and backer.

...

Ah, I see you had to go create trouble when you went looking for it.

Seriously though, thanks for writing that out. What you're describing makes sense to me, based on what I've witnessed. Lots of barrel length, fast twist rate and some serious tipping of the powder jug can do strange things.

Correct me if I'm wrong, but my impression was the 90gr SMK turned out to be a relatively short-lived experiment among Service Rifle shooters. The combination of extreme bullet weight (length), small powder capacity and short barrel length never led to the gains that were supposed to be possible over the 80gr SMK (or Noslers, I really like Nosler Custom Competition bullets). I just happily went along shooting the 80gr Nosler CC at 600 yards while I was competing in Service Rifle in NRA Highpower and CMP matches. The barrel on my old Service Rifle used to hammer with the 80s over a max charge of Varget.

Back to the 75/77gr magazine bullets, I really liked them and had several loads that would shoot really well. Again, they were all pretty much book MAX charges of RL-15, Varget or H4895, with Varget being my preferred powder when it was available. But my last season and a half of shooting Highpower, I went back to the 69gr magazine bullets because I was able to actually get a bunch to use. This was around 2010, when the Obanic was getting going. And out to 300 yards, I'm still not convinced the higher BC of the 77s always beats the extra speed of the 69s. But I could never hit the velocities with the 77s that others claimed.

Apologies for the thread drift rebs. If you'll note one thing from my talking about my experiences shooting heavy bullet .223 loads, it's that my best accuracy was usually with loads right at the upper limit of the charge ranges with RL15 or Varget. And I'm not the only one who lived in the zone either.