5.7 x 28

[Aschlegel69]

I just picked up some Lyman dies for my 5.7. This is the first time I am attemting to load this cartrige. What is the recomended case length. Do I really need to trim the cases?

With the primer shortage all I could find was Federal Small Rifle, What is the best primer to use?

I really would like to load a 27 or 30 grain FMJ. Does any one make light FMJs for the .224? I have the IOM. I have heard that you can spring the lower fraim with too hot of a load behind a heavy bullet.

I want a good, reliable, penetrating round.

 

[FN5.7shooter]

An important issue with 5.7X28 reloading is shoulder position. First learn how to measure this. It can be done with the barrel removed from the gun just compare your resized cases to factory ammo. Get dies that move shoulder back to within .003" of factory ammo, early RCBS dies will not do it. Yes you will have to trim. Some use small rifle primers. You may not see effects of pressure with them so be careful.
The 5.7 frames don't have any problem with any rational loads. Just stay away from lousy reloading and you will be fine.

 

[RyanM]

Do I really need to trim the cases?

Pretty much all bottleneck rounds have to be trimmed. How often will depend on the gun, the loads, etc. Lengths, hopefully will be listed in a reloading manual, or maybe with a case trimmer. It should have a maximum length, and a trim-to length.

 

[Peter M. Eick]

My shooting buddy and I have been debating this for his 5.7's. The trimming that is.

His 5.7's are both blowback not locked breach, so how much trimming do you really need to do? If they case is a bit long, it will still chamber and fire (we believe) up until the disconnect kicks in.

The current plan is to take one round and shoot without trimming and keep doing that until we figure the limits between trimming.

We are not sure what is going to happen here, so please consider this an experiment to understand the results.

My bet is the brass will stretch enough that it will separate before the disconnect kicks in.

 

[Walkalong]

For once fired brass, you will most likely not have to trim the cases. They will be short enough to fit the chamber. Eventually you will have to trim them.

As far as moving the shoulder back. The actions are blowback. The shoulder moves WAY forward when fired. When you size it back you will be moving it back .030 or more.

Yea, it's unsettling when you are used to a shoulder moving back a few thousandths at most. This brass fails at that juncture after a few firings. I have not shot one case enough to experience it yet. You will not have case head separations unless you grossly overcharge a case. The neck will separate first. Peter M. Eick's test will be a good one. Of course, when it fails depends on how hot each load is. Some are getting only 3 firings from hot loads, and others are stretching it to 6 or 7.

I have used CCI 500 and WSP primers with good results. I am sure others will work fine. Some folks use small rifle primers in it. That is fine too. Just don't switch indiscriminately without working a charge back up.

I have shot 34 to 50 Gr bullets in my AR57.

Some over at th 5 7 Forum say you don't have to ream/swage the primer pockets, but I disagree. I tried it both ways. It will make priming MUCH easier if you do. I just gave em all a light twist with my RCBS chamfer tool. It made priming much less of an adventure.

Ramshot and Accurate both show a little data. I have worked up a little on my own as well. So have folks over on the FiveSevenForum.


Here is a thread that might help a little.

Or this thread on the FiveSevenForum.

The FiveSevenForum is a great place for answers. Good luck, and feel free to PM questions. AC

 

[FN5.7shooter]

I have experimented with trim length and getting more than .005" long is not good. The gun locks up and the velocities went very high. You risk jamming the bullet and increasing pressure and then losing the case head and the gun frame. Why on earth would a person try to defeat the most unique blow back system ever invented over a little trim work. Get another hobby that requires less precision or stick with straight wall pistol ammo. You can't move the shoulder .050" inch and not have to trim after sizing.
The 5.7 handgun is not a simple straight blow back system. Study the system a little know what the levers L1/L2 are and what it does before you decide to reinvent the ammo for the gun. It is unique in the world and very ammo sensitive. Depending on the disconnect to save you when you don't know how it works will surely lead to poor results.

 

[Walkalong]

The 5.7 handgun is not a simple straight blow back system

True.

The AR57 is, and I am not sure about the PS90. All of them allow the neck to move way forward on firing though.

The 5.7 handgun.............It is unique in the world and very ammo sensitive.

Yep. I have a lot more leeway in my AR57. Lots of stories of the 5.7 hand gun and bad reloads ending poorly.

 

[FN5.7shooter]

I do load development with a Contender.
Because of the operating system one can not just clean and reload the brass.
All the brass I have measured has had forward shoulder movement of .035" to .050" depending on the load bullet weight what is was fired in and such. All of the brass needed trimming after resizing.
I don't know about lots of stories of blow ups but the one with the most "press" was from a reloader who was very careless. He didn't get the trim to length correct in his first account of the incident, he used a LEE hand press to reset a shoulder .050" and only had about +.005" margin, he used a bullet weight that is not well documented, before the last shot he had several lock ups of the gun with no ejection/extraction a sure sign of problems in this system. I would say this is not the way to reload. One needs to stick close to factory specs with this one and stop if you have a hiccup.
Yes one should trim 5.7X28 after resizing.

 

[Walkalong]

OK, plenty of, not lots of.

At any rate, the moral of the story is to be careful. Like FN5.7SHooter posted, it can be a finicky little bugger.

It is unique in the world and very ammo sensitive.

I agree. Don't be alarmed, just be careful.

 

[Aschlegel69]

You guys have some very good points that I had not considered. Such as excessive case length causing higher pressures and bad results. I have a reading trimer that I use for my rifle brass but it does not work well with the Five seveN brass. What is a good trimmer the the 5 7 brass?

 

[Walkalong]

I had to modify an RCBS collet (#4 I think) to fit mine. I have a Possum Hollow trimmer for .223, and it can be adjusted to work on 5.7 X 28.

I have only loaded once fired brass so far and have not had to trim yet. It may be different for the pistol. The safe way is to go ahead and trim.

 

[BSlacker]

I have a reading trimer that I use for my rifle brass but it does not work well with the Five seveN brass. What is a good trimmer the the 5 7 brass?

The Redding trimmer has the universal collet and most of these have trouble going as small as the 5.7X28mm rim size. I am using a Lyman Accutrimmer that uses shell holders and with the shaft for a small powered screwdriver. Trimming may not be needed for the brass fired in a rifle I don't know.

I had to modify an RCBS collet (#4 I think) to fit mine.

Some of the early RCBS dies would not resize the shoulder. They have fixed this.

 

[Walkalong]

I am using Lyman dies, same as the OP.

 

[LightningMan]

With what little reloading I have done with the 5.7x28mm, I have found the FNH ammo, like the SS195 LF & the SS197 SR will be just under the limit for max. case length of 1.143 after firing. The lengths I have been getting are around 1.138-1.140, so you could reload them without trimming, but once more and you will be over that, and you will have to trim them. I have been using a Lyman Universal Case Trimmer with good results to do my 5.7 brass. I like using the lighter grain bullets and most have been HP or SP, as I have been unable to find any 30 to 35 grain FMJ bullets yet. LM

 

[Walkalong]

I bought my 34 Gr bullets before things got so bad. I have some Winchester 45 Gr SP's and 46 Gr HP's from way back that shoot well in it. They will hold me for some time until things catch up.

 

[Aschlegel69]

I just found some Dogtown 34 grain hollow points on Midway.com If only someone would publish data for the lighter grain bullets in the fiveseven.

 

[LightningMan]

Aschlegel69, both Ramshot & Accurate have data for the 35 grain V-max bullets. Ramshot lists TrueBlue and Accurate lists AA#5 & AA#7 for the 35 grainers. Your 34 grain bullets should be good with those data's listed, but start with the bottom and work up from there, to be safe. LM

 

[HK SD9 Tactical]

I have loaded this round with projectiles from 27g to 55g using True Blue powder.

I ALWAYS trim the brass using the Hornady Cam Lock trimmer with a modified #37 shell holder. 1.133in is my standard but I have trimmed shorter, never below 1.128in though. Shoulder movement can be up to .050in. Brass must ALWAYS be resized before reloading and trimming is recommended. I have loaded subsonics (55g Sierra Game King) and I will not use the 55g projectile for anything else except sub sonics, even if I did do some chrony data for 5.0 grains of powder. NEVER EVER EXCEED 5.0 grains of powder using a 55g projectile. I have never swaged the primer pockets, it is not required. Pressure builds fast and there have been reports of KB's. I have never experienced one and do not intend to.

Failure to eject properly and feed are indications you have gone too far even without other pressure signs. If the magazine pops up, you have gone too far.

With the exception of subsonics, I prefer loads with projectiles between 27g and 40g.


Load data: here