Has anyone converted a bolt action to 5.7x28?

[Wm Cook]

New member, first time posting.

Has anyone converted a bolt action to 5.7x28?

I have a Cooper Model 38 bolt action chambered in 17CCM. The 38 Cooper has a tiny action that would fit the 5.7x28 case and the bolt face and the clip (with a very slight modification) is one for one with the 5.7FN case. To feed the rimless case the back of the clip needs a slight shim.

This is about bolt action rifles chambered in 5.7 x 28. If you have any experience with this I’d appreciate you sharing your experiences.

I do have a couple of specific questions. First is the brass life of the 5.7 brass in a bolt action and second is your experience with any inherent problems with accuracy. Any other thoughts would be appreciated.

I'm expecting Hornet velocities with 35/45 grain bullets running from subsonic to 2.800 fps. Cast and jacketed bullets will be used according to the velocity I’m looking for and the loads intended use.

My experience: I’ve been handloading cartridges between 17’s to 30 cal's for 30 plus years. Velocities have run from subsonic to 4000 fps. Competition was limited to 6PPC short range benchrest. In theory I believe bolt action rifles should put all five shots through the same hole (at least that's a given I take into every project). If they don't, the weak link could be me, my bench technique, bench equipment, the barrel, powder/bullet, rifle platform or the wind.

Most everything except the wind can be corrected with time and money. For me the fun is chasing an accurate load. That’s therapy for me. Thanks, Bill.

 

[matthias]

Yes it can be done.
Brass life is almost indefinite
2800 fps is possible
Accuracy can be good. I have several that shoot under an inch. And two that are regularly under 1/2 for 3 shot groups

Feeding and ejecting is the issue. Mostly ejection.
Single shot encore rifle , 580 ss conversion, 581 mag fed conversion, rem 700 ss conversion, savage 25 ss conversion. The list goes on.

 

[scasa]

I started to make one but in my research I read that someone (FN) had a prototype but didn't get the required accuracy so that's as far as it went. I went a different way (7.62x25). But I see somebody has done several with decent accuracy. That's good to know in case I get the bug again

 

[swd]

About 10-12 years ago I converted a CZ527 Hornet to 5.7x28. It never did feed well and the performance was a lot less than what we were hoping for. If I recall factory ammo went around 2450 FPS. A 22 Hornet performs considerably better. I wouldn’t do it again.

 

[matthias]

The factory ammo is not great for speed or accuracy. Hand loads were the only way to get real performance. It is on par with a hornet when hand loaded. Definitely a fiddly project both the build and the reloading.

Where is your cz now? Would love to see what you did.

 

[Wm Cook]

Matthias, do you bump the shoulders/neck size or FL size. Whose dies are you using? Thanks.

Yes it can be done.
Brass life is almost indefinite
2800 fps is possible
Accuracy can be good. I have several that shoot under an inch. And two that are regularly under 1/2 for 3 shot groups

Feeding and ejecting is the issue. Mostly ejection.
Single shot encore rifle , 580 ss conversion, 581 mag fed conversion, rem 700 ss conversion, savage 25 ss conversion. The list goes on.

Yes it can be done.
Brass life is almost indefinite
2800 fps is possible
Accuracy can be good. I have several that shoot under an inch. And two that are regularly under 1/2 for 3 shot groups

Feeding and ejecting is the issue. Mostly ejection.
Single shot encore rifle , 580 ss conversion, 581 mag fed conversion, rem 700 ss conversion, savage 25 ss conversion. The list goes on.

 

[swd]

The factory ammo is not great for speed or accuracy. Hand loads were the only way to get real performance. It is on par with a hornet when hand loaded. Definitely a fiddly project both the build and the reloading.

Where is your cz now? Would love to see what you did.

It was a build for a client, don’t know if he still has it or not. He was mostly interested in shooting factory ammo. Fiddly is definitely the right way to describe it, lol

 

[matthias]

I use rcbs fl dies. Bump about 3 thousandths.

My next 5.7 project is going to be using cmmg ar conversion magazines shortened to fit a bolt action bottom metal set up.

 

[Ggmac]

Cut a 5.7 case in half . Look at the extractor groove and how much meat is around the primer . Very little ! The one that i did , had shorter than normal brass life . 2 reloads and the primer would fall out .
Savage action , ptg bolt head , only moderate loads .
Not worth the effort unfortunately. Still have the reamer , i think .

 

[NorCalMikie]

Savage Model 10. PITA!! Little bitty round has to be pointed up and into the chamber before you even think about closing the bolt. Did I say PITA??

 

[matthias]

Elite ammunition has very thick brass they spec out. Case capacity is down but can solve some of those issues.

Big thing I have made sure of is making sure the entire case is in the chamber all the way to the extractor cut. Helps with case support.

Definitely a fiddly project with it's own challenges.

 

[ebb]

Racer Bob bought a pistol and used a 5 gallon bucket of brass he got from the PD where he worked to make his own ammo. He said that primers were lose quickly with factory brass. Next time I see him I will mention the Elite brass.

 

[ebb]

Mr Cook have you looked at the 22TCM?

 

[Ggmac]

Elite ammunition has very thick brass they spec out. Case capacity is down but can solve some of those issues.

Big thing I have made sure of is making sure the entire case is in the chamber all the way to the extractor cut. Helps with case support.

Definitely a fiddly project with it's own challenges.

They cant make it thicker where it needs to be . The primer is a set diameter and the extractor groove is where it is , cant move it or make it more shallow .

 

[Ggmac]

Mr Cook have you looked at the 22TCM?

Racer Bob bought a pistol and used a 5 gallon bucket of brass he got from the PD where he worked to make his own ammo. He said that primers were lose quickly with factory brass. Next time I see him I will mention the Elite brass.

Mark look at my post ! Cant make someting thicker if theres no room .

 

[Wm Cook]

Ebb, the TCM would have the right results but the bolt face on the CCM is for a .307 case head. TCM is about .378 or there abouts.

 

[matthias]

They cant make it thicker where it needs to be . The primer is a set diameter and the extractor groove is where it is , cant move it or make it more shallow .

I see what you are saying. Yes they made the web of the case thicker. Not the area for the extractor cut.