Who owns a CZ MTR,or an RAP?

[grayfox]

After some further thought (and some dinner), that probably wouldn't work, b/c the bolt head takes up that space (or a lot of it) between the receiver and bolt chamber...

[Lemonaid]

grayfox, try this simple experiment and see if it improves feeding.
In the mag well, trigger side, put some layers of tape and test out feeding with the magazine inserted. The tape will take up the slop and greatly reduce how much it will pivot downward.
If it improves feeding you may want to do what I did and use some bedding material (JB Weld) and your favorite mag coated with release agent (wax works fine) and use some elastics to rock the magazine into the forward upright position while it cures overnigth.
This made some magazines a tight fit (E-lander), and the mags don't drop free but the improved reliability for me was worth it.

[grayfox]

Definitely thinking on that. I tried some tape on the back of the mag to press it fwd a bit, some help. Then tried jamming (a temp fix) small rod to push/rock the mag fwd. again, some help...
Latest thing was I went back to re-read some threads... found this one (all 4 pages).
http://www.65grendel.com/forum/showthrea...tock/page4

So I took a brand new 10-rd (cpd) dura-mag and clipped off one bottom coil, "360 deg", of steel. Tried that one just now and got an initial, 4 for 4 feeding. So this approach might work. more testing. granted, bolt-cycling needs to be crisp, but it was doable.
Also ordered a couple elander mags as the issue as spoken in the threads seems to indicate it is kind of mag-specific... maybe.

[grayfox]

Question for those who "polished the feed ramp" -- what exactly did you do, did you widen it at the top, just polish it overall, change the feed angle...?

[Rosecrans1]

Grayfox........time really helps with the feeding of shells in the RAP-Grendel. That said you still need to be able to feed bullets, period. The heavier the mag spring, the worse the RAP Grendel feeds out of the box. I had great success with the ASC 5 round mags. When I took my RAP apart and cleaned all the oil off everything and put it back together, I only torqued the action to 50"-lbs as I think 60 to 80 that Ruger calls for on their plastic stock has a huge effect on feeding. I ran shells through the gun when I took it out of the box and it sucked. After I had it apart and back together at the lower torque settings, it fed much better. Not perfect but substantially better. I used a drop of blue Loctite on the action and rail screws as well.
I bought a stock someone had on Gunbroker for the RAP Grendel complete with the factory Cprod mag for 60 bucks last Summer and when I put my bottom metal, (OK, it's not really metal), in this new factory stock with the action, it fed perfect! There is a lot of open tolerances in these RAPs and your aftermarket stock would be no different.
So, long story short for feeding issues: No heavy mag spring! (ASC 5 round worked best for me). Check the torque of the action. (Mine liked less than Ruger calls for). Experiment and make sure you thread lock the action. Shoot it. The more it's shot, the better the action smooths out and feed issues disappear! Hope this helps a little.

[grayfox]

After trying several mfr-mags, fiddling, polishing, etc, trying an mdt chassis, nothing seems to cure the failures to feed. I called Ruger and they said maybe a recvr problem, gave me an RMA. So sending it in to them to see what they can do.

[A5BLASTER]

After trying several mfr-mags, fiddling, polishing, etc, trying an mdt chassis, nothing seems to cure the failures to feed. I called Ruger and they said maybe a recvr problem, gave me an RMA. So sending it in to them to see what they can do.

I'm going to give this cz varmint a few more months. If I can't get the mag issues figured out by mid summer. I will be ordering anouther howa and having a custom 24 inch barrel put on it.

Rifle is stupid accurate but I can't stand a bad feeding mag system.

That's why I never got into the RAP. I know it was going to have issues with the ar mags. Seems like the CZ has the same issue with its mags as well.

[grayfox]

I think, in my simple-engineering style mind, that the RAP problem has to do with switching it from a centerfeed (as the original mags) to a right-left feed (as an AR mag). The feed ramp in the front of the rcvr has been left as a single ramped slope/gap (which also works for the AI style 243, 6Creed/308 etc), whereas if you consider the AR, there is a double feed ramp, as in the "M4" style. It extends into the receiver metal but just the fact that each round has a guide more lined up than it would in a single-ramp setup... anyway that's what came to me last night as I was looking at the action and feed path. the tip -- about 90% of the time -- hits the back of the barrel, the vertical flat "wall" about 0.2" or so below the chamber entry. there are 2 spots of brass marks (90 gr Fed factory AE's) one lower left and one lower right, from the chamber entry.
I don't necessarily need it to feed suuppper-slow on the bolt..... but at a normal bolt cycle rhythm, we should be talking near 100% feeding... just like any other rifle would.

[A5BLASTER]

I think, in my simple-engineering style mind, that the RAP problem has to do with switching it from a centerfeed (as the original mags) to a right-left feed (as an AR mag). The feed ramp in the front of the rcvr has been left as a single ramped slope/gap (which also works for the AI style 243, 6Creed/308 etc), whereas if you consider the AR, there is a double feed ramp, as in the "M4" style. It extends into the receiver metal but just the fact that each round has a guide more lined up than it would in a single-ramp setup... anyway that's what came to me last night as I was looking at the action and feed path. the tip -- about 90% of the time -- hits the back of the barrel, the vertical flat "wall" about 0.2" or so below the chamber entry. there are 2 spots of brass marks (90 gr Fed factory AE's) one lower left and one lower right, from the chamber entry.
I don't necessarily need it to feed suuppper-slow on the bolt..... but at a normal bolt cycle rhythm, we should be talking near 100% feeding... just like any other rifle would.

I noticed on the cz. The bullet tip doesn't hit the ramp but the bullets body aka ojive area slam's into the ramp. I have a big build up of copper on the ramp, I had to clean off last night.

Think I'm going to try and open the feed lips up a lil bit, so the round sits higher when the bolt is pulled back to grasp anouther round.

[grayfox]

So. Sent the RAP in for Ruger to look at it, they turned it around really quick, just got it back today, so a little over 1 week, maybe 1.5, total.
They said they replaced the bolt and added a new (CPD) mag, then were able to fire 20 rounds of Hornady without any misfeeds, so they called it fixed.
Now that I have it back, first thing I did was to determine torque settings they used on the factory stock, and came up with Rear: 40 in-lb, front: 60 in-lbs.
Then I cycled several Hdy custom (123 Sst) through with both their mag they sent and 1 of mine (dura-mag), the Customs did cycle although I will say you need to be "crisp" with the first part of the bolt push. One sst - the last one- hit the rear wall of barrel below the chamber but when I re-cycled the bolt a bit it lined up and fed on in. So that is an improvement I will say. I also tried a few 90 Tnt's Federals, and all but the last one would feed, again being "crisp" in the push-strip. Last one went in when I fiddled the bolt a bit. Prior to this no amount of fiddling would help.
Not faultless, not 100% feed that I would like but I will say it is an improvement.
So I re-assembled into the MDT and same story, so looks like it's improved.
Don't have an explanation as to why a bolt swap would do this but it looks like it did.
(Footnote, I was surprised at the 60 in-lbs, when I had the factory stock at on at first I was more like 35 maybe 40, can't remember.)

So we will do some shooting with it this week to see how it does!
I still really like the Mdt stuff...

[FLshooter]

So. Sent the RAP in for Ruger to look at it, they turned it around really quick, just got it back today, so a little over 1 week, maybe 1.5, total.
They said they replaced the bolt and added a new (CPD) mag, then were able to fire 20 rounds of Hornady without any misfeeds, so they called it fixed.
Now that I have it back, first thing I did was to determine torque settings they used on the factory stock, and came up with Rear: 40 in-lb, front: 60 in-lbs.
Then I cycled several Hdy custom (123 Sst) through with both their mag they sent and 1 of mine (dura-mag), the Customs did cycle although I will say you need to be "crisp" with the first part of the bolt push. One sst - the last one- hit the rear wall of barrel below the chamber but when I re-cycled the bolt a bit it lined up and fed on in. So that is an improvement I will say. I also tried a few 90 Tnt's Federals, and all but the last one would feed, again being "crisp" in the push-strip. Last one went in when I fiddled the bolt a bit. Prior to this no amount of fiddling would help.
Not faultless, not 100% feed that I would like but I will say it is an improvement.
So I re-assembled into the MDT and same story, so looks like it's improved.
Don't have an explanation as to why a bolt swap would do this but it looks like it did.
(Footnote, I was surprised at the 60 in-lbs, when I had the factory stock at on at first I was more like 35 maybe 40, can't remember.)

So we will do some shooting with it this week to see how it does!
I still really like the Mdt stuff...

Hope it works out for you. My RAP ,which is pretty much the same set up as yours with the MDT chassis, feeds flawlessly w/ASC 5 & 10 rounders. I’ve only tried 123 grain Hornady ELDM handloads. I’m working up a load right now. Starting at 25.2 g of H335 working it .3 grains up every 10.
It definitely did not like the 27.3 grain of H335 that my AR likes. The bolt stuck twice. I posted it last week. The barrel was also very dirty because I never cleaned it when I got it. Anyway I’m not having any problems now. It’s a very accurate rifle.

[grayfox]

Took the RAP to the 100 yd range today, in the Mdt chassis. I was much happier with feeding and the shooting is still really good for factory ammo. I shot 1 grp-4 of Hdy 123 sst, 1-4 grp of Federal Tnt 90, and several groups of Mdy Match black, more sst, and some Hdy gunner 123's. Pix later after dinner.
The first set, 3 < 1" then I tweaked the scope 3 clicks left and the fourth shot fine (but obviously left of the others). The Tnts next, 3< 1" and fourth ~1.25 or so.
Feeding, the sst's fed fine, the Tnts 3/4, the 4th I had to fiddle to feed (inventing a new term here, Fitf...!!) but it did. The hdy AG all fed, I think one more maybe eldm was a fitf. In all 22 rounds and nice groups.
I used their newly-supplied factory mag (a CPD), one of my new dura-mags, even tried one of my reduced coil mags (cut 2 from the spring)... well that one sort of worked but didn't feel as good as the std spring-mags.
I didn't especially rock the mag fwd or back, just snapped it up into the magwell.
The bolt, as mentioned earlier, you need to be a bit crisp -- I don't know how to quantify it exactly -- if a round hits below the chamber entry I just back it off and the round seems to line up ok, then feed.

Total weight w/ empty mag and my chassis, 9.75 lb give or take.
I'm thinking on swapping out my Vortex 4-12x4 tactical for a PA 4-14x44 to give me some more magnification.

But overall I think it's in the game now.

Now I can do some loads with my mgspd and work up some loads for it. Hoping for 90's, 100 ttsx, and 123's. Maybe some 100 Nosler or Eldm's too.

I do like these 5R barrel lands...

[FLshooter]

Took the RAP to the 100 yd range today, in the Mdt chassis. I was much happier with feeding and the shooting is still really good for factory ammo. I shot 1 grp-4 of Hdy 123 sst, 1-4 grp of Federal Tnt 90, and several groups of Mdy Match black, more sst, and some Hdy gunner 123's. Pix later after dinner.
The first set, 3 < 1" then I tweaked the scope 3 clicks left and the fourth shot fine (but obviously left of the others). The Tnts next, 3< 1" and fourth ~1.25 or so.
Feeding, the sst's fed fine, the Tnts 3/4, the 4th I had to fiddle to feed (inventing a new term here, Fitf...!!) but it did. The hdy AG all fed, I think one more maybe eldm was a fitf. In all 22 rounds and nice groups.
I used their newly-supplied factory mag (a CPD), one of my new dura-mags, even tried one of my reduced coil mags (cut 2 from the spring)... well that one sort of worked but didn't feel as good as the std spring-mags.
I didn't especially rock the mag fwd or back, just snapped it up into the magwell.
The bolt, as mentioned earlier, you need to be a bit crisp -- I don't know how to quantify it exactly -- if a round hits below the chamber entry I just back it off and the round seems to line up ok, then feed.

Total weight w/ empty mag and my chassis, 9.75 lb give or take.
I'm thinking on swapping out my Vortex 4-12x4 tactical for a PA 4-14x44 to give me some more magnification.

But overall I think it's in the game now.

Now I can do some loads with my mgspd and work up some loads for it. Hoping for 90's, 100 ttsx, and 123's. Maybe some 100 Nosler or Eldm's too.

I do like these 5R barrel lands...

Good deal! thanks for the update.

[grayfox]

Feeding check and mgspd testing with Hdy custom, eldm's, and some handloaded 129 ablr's and 129 sst's (Cfe 223) tonight if all goes as planned. The 129's will lengthen the cartridge, which should be a help: loading is limited to mag length about 2.275-2.280. Chamber lengths the sst will go 2.340 and the ablr's 2.330+.
I also did a quick visual to see how much difference in case room the seated bullet would do ablr vs 129 sst. the answer appears to be, not much. the boat tail on the ablr is longer but it sticks a tad deeper... overall take-up room seems to be a wash.
Will use the cpd dura mag's.

[grayfox]

Well, first I needed to zero the new scope I put on.... forgot about that :/
Then the chrono work began. Mostly a scoping type of shot groups, 3 each.
Narrowing in will come later.
From my previous bolt-action and within book limits I chose some loads that ought to be ok...
that is, for my gun, ymmv.
129 SST, Hornady brass with cci450, coal set to 2.285. The mags will fit 2.293-2.295.
129 Ablr's, Hornady brass with cci450 again.
I used CFE 223, at 30.4, 30.7, and 31.0 grs. No crunching felt. No hard bolt lifts, no pressure signs.

Also shot some Hdy 123 sst's, 123 eldm (Hdy Black) and Federal Tnt 90's, all factory.

This barrel is kind of fast. Which is nice. It's resting in the Mdt AR-mag-well chassis for Grendel, and a 4-14x44 PA ffp scope on top.
I do like this RAP.

123 Sst custom: 2568 sd-15.5
123 Hdy Blk Eldm: 2544, sd-24.8
90 Tnt Federals: 2970, sd-21. This 2970 is 70-100 ft/s faster than any of the 20" bbls I've owned.

Now 129 Sst handloads:
30.4 gr: 2488, sd-14.7
30.7 gr: 2514, sd-8.6
31.0 gr: 2543, sd-15.6

129 Ablr handloads:
30.4 gr: 2477, sd-16.5
30.7 gr: 2497, sd-8.6
31.0 gr: 2516, sd-13.7

Both 129's shot nicely, I think I'll concentrate on the vicinity of 30.6-.7-.8 for both of them. (But will also be feeding 123's, maybe my 100 ttsx's)
The Ablr is of course a premium bullet and nice 0.530 BC, but the Sst is not bad, more economical and still 0.495.

At 2500 ft/s or so I will have plenty of range for what I might shoot this one.

Feeding was acceptable, only 1 FiTF (my new term, "fiddle to feed") and 1 Ftf out of ~35 rounds and 2 mags (the Cpd-dura mags).

Did I mention that I like this RAP?

[A5BLASTER]

Well, first I needed to zero the new scope I put on.... forgot about that :/
Then the chrono work began. Mostly a scoping type of shot groups, 3 each.
Narrowing in will come later.
From my previous bolt-action and within book limits I chose some loads that ought to be ok...
that is, for my gun, ymmv.
129 SST, Hornady brass with cci450, coal set to 2.285. The mags will fit 2.293-2.295.
129 Ablr's, Hornady brass with cci450 again.
I used CFE 223, at 30.4, 30.7, and 31.0 grs. No crunching felt. No hard bolt lifts, no pressure signs.

Also shot some Hdy 123 sst's, 123 eldm (Hdy Black) and Federal Tnt 90's, all factory.

This barrel is kind of fast. Which is nice. It's resting in the Mdt AR-mag-well chassis for Grendel, and a 4-14x44 PA ffp scope on top.
I do like this RAP.

123 Sst custom: 2568 sd-15.5
123 Hdy Blk Eldm: 2544, sd-24.8
90 Tnt Federals: 2970, sd-21. This 2970 is 70-100 ft/s faster than any of the 20" bbls I've owned.

Now 129 Sst handloads:
30.4 gr: 2488, sd-14.7
30.7 gr: 2514, sd-8.6
31.0 gr: 2543, sd-15.6

129 Ablr handloads:
30.4 gr: 2477, sd-16.5
30.7 gr: 2497, sd-8.6
31.0 gr: 2516, sd-13.7

Both 129's shot nicely, I think I'll concentrate on the vicinity of 30.6-.7-.8 for both of them. (But will also be feeding 123's, maybe my 100 ttsx's)
The Ablr is of course a premium bullet and nice 0.530 BC, but the Sst is not bad, more economical and still 0.495.

At 2500 ft/s or so I will have plenty of range for what I might shoot this one.

Feeding was acceptable, only 1 FiTF (my new term, "fiddle to feed") and 1 Ftf out of ~35 rounds and 2 mags (the Cpd-dura mags).

Did I mention that I like this RAP?

Looks good gray.

That 31 grain charge and velocity is close to what I got with cfe223 and the 129 ablr in the howa I had. It just keep falling apart on me with a 20 degree temp change.

Liking the h4895 powder much better, my CZ loves that bullet being pushed by h4895. I'm working at 2.300 length but have a tinny bit of room leavt in the mag I work up and down a bit to try and dress it up some.

If you have some h4895 you might be surprised with it. I seen some data on Johnny' s reloading with 129 ablr and ar-comp.

I might give it a try but that load I worked up with h4895 is very nice.

[grayfox]

yeah the temperature thing is the main bugaboo for CFE. I've got some h4895...
is it in the nosler book or where did you start...

[A5BLASTER]

yeah the temperature thing is the main bugaboo for CFE. I've got some h4895...
is it in the nosler book or where did you start...

Yep nosler has some data for it. I found it on their online website.

I still need to buy the nosler data book, don't have that one.

I started with their mid range load and worked up. I have to vibra settle the load I'm running, it's still a bit crunchy and is compressed.

But in my CZ the load work was so well behaved and the sd and es is so good, that I just can't help but run it. Brass and primers showed zero pressure signs but it has to be above sammi pressure. Shouldn't be a problem in a bolt action.

I still need to play with the seating depth a lil and see if I can tighten it up.

I'm useing Starline brass, but if your useing hornady brass it might not be as compressed as my load, since the hornady has a lil bit more case volume then the starline.

[grayfox]

I took my RAP tonite for some 130 Federal factory, and 115 Tac-tx. Both shot pretty well, around 1" maybe a bit better.

The Tac-tx, 4 shots, 2528 avg and SD-12.
The 130 Federal 4 shots, 2420 avg and SD-7.

They seem to have same POI as the 123 hornady factory, both sst and eldm. which is nice but we'll see if that holds up.

[FLshooter]

I took my RAP tonite for some 130 Federal factory, and 115 Tac-tx. Both shot pretty well, around 1" maybe a bit better.

The Tac-tx, 4 shots, 2528 avg and SD-12.
The 130 Federal 4 shots, 2420 avg and SD-7.

They seem to have same POI as the 123 hornady factory, both sst and eldm. which is nice but we'll see if that holds up.

How is the rifle feeding since you got it back from Ruger?