JRC 40SW feed issues

[Forgetful]

I would love to find a replacement factory round that chambers more reliably than these AE40SW 180gr rounds, but have started looking for molds. There is no curve to the nose of these bullets, and often get stuck on the feedramp with their fat/wide meplat. I was thinking if someone made a 40 like you see in 9mm ball, it might not catch on the ramp half the time.

So I was looking at some mold sites and came across ballisti-cast molds with a few offerings of RNFP and RN's for the 40/10mm. I'm not reloading this round, and wasn't planning on it. But I have a stockpile of thousands of these AE rounds which I figured would run great in the JRC, and a buddy of mine wants to buy them, and he's reloading for the 40 too. I don't want to buy another set of dies just for this carbine, I just want to load rounds in it that work better. We'll come to some agreement where I cast these and he reloads them, and I sell him my stockpile and he sells me reloads back, or something along those lines. This way I can pick a mold that should work in his pistols and my JRC.

I would love to keep the boolit 180gr+ so the velocity is below 1150fps. Any suggestions on molds I could try? I'm currently looking at this one:

Ballisti-Cast 959H 40-10mm RNFPBB (http://www.ballisti-cast.com/boolits/boolits/prints/959H%2040-10mm%20RN%20FP%20BB.pdf)

[Jupiter7]

NOE makes a nice 180gr RN mold.

http://noebulletmolds.com/NV/product_info.php?cPath=39&products_id=231&osCsid=a1rtakn2c9aco9d7o2vqet8bd4

[dondiego]

You should be able to keep any bullet weight to below 1150 fps.

[Forgetful]

You should be able to keep any bullet weight to below 1150 fps.

Sure but max ballistic coefficient, I want the full weight at max power.

[Forgetful]

NOE makes a nice 180gr RN mold.

http://noebulletmolds.com/NV/product_info.php?cPath=39&products_id=231&osCsid=a1rtakn2c9aco9d7o2vqet8bd4

That looks like a winner.

[Jupiter7]

That looks like a winner. I bought one just now to try it out.

I recently bought it for 3gun competition. It feeds like butter.

[plainsman456]

Like was said NOE makes good 40S&W molds,i have the 160 and the 180.
They both feed with no problems in my Browning.

[edctexas]

+1 for the NOE Mold. I have one and it throws nice boolits and they shoot well in a rifled barrel. I am still figuring out the mysteries of an H&K poly barrel with this boolit. Shoot well but leads.
Ed C

[Forgetful]

I have one ... but leads.

How hard were they, or what alloy and treatment did you use?

[Forgetful]

So I've contacted JRC and they're sending me a heavier buffer and a new feed ramp. Apparently my model (only ~1 year old) has free updates for it. You guys should check your models. Mine came with the carbine buffer tube extension so I could use larger rifle buffers.. Looks like these buffers need to be in the 10oz to 16oz range.

My feed and ejection issues might go away completely! The problem was I selected an ammo that worked well before it was broken-in. During the break-in, it self-polishes the internals, speeding up the action. Action became too fast.

I still want to slow the powder down and lower the pressures to get max velocity, though!

[Pinsnscrews]

What powder are you using currently? Is your intent to get 10mm velocities with the LRP or more consistant ES? I have been considering upping my 10mm to LRP reloads, but understand I will need to get a stiffer hammer spring due to the thicker cup not always triggering behind a pistol hammer strike.

[Forgetful]

What powder are you using currently? Is your intent to get 10mm velocities with the LRP or more consistant ES? I have been considering upping my 10mm to LRP reloads, but understand I will need to get a stiffer hammer spring due to the thicker cup not always triggering behind a pistol hammer strike.

No idea what powder are in these factory AE 180gr rounds. They're meant to use 35000psi and get to 1000fps in 6 inches. I want to use Herco, Alliant, Universal, and LongShot powders and find one that cycles slower but yields higher velocities. Slower powders such as Herco would need a stronger primer IMO, and I could have went to LPP first instead of LRP... but my set of primer tools are for large rifle and 50bmg. It should be fine if the hammer has enough energy to consistently detonate these cups.

I don't expect 10mm velocities. Just want to lower the pressure with a slower powder and maintain current velocities at a minimum. These rounds were intended for pistols, not an 18.6" barrel. I figure I can take some energy out of the bolt cycle using more of the barrel for acceleration.

Logically:
1) slower powder = lower pressure
2) lower pressure = more time before bolt cycles
3) slower powder = inconsistent burn rate for SPP, increase to LRP
4) larger primer = higher initial pressure offsetting slower powder peak pressure to get boolit moving
5) larger primer = less charge
6) less charge = more room in case
7) more room in case = 10mm

This was sort of my line of thinking, anyway.

[Pinsnscrews]

You might try running a Google search to locate Tear Down info for that round. it would halo you to know what weight and powder type was loaded from the factory so You could compare from there with other load data. Another site I am a part of does tear downs, one of the members has a good powder inormation database he can reference. Maybe one of the .40S&W specific forums.

[Forgetful]

Maybe one of the .40S&W specific forums.

I tried some broad searches but nothing is coming up. I'm not too worried about load data, I figured I'd start from a safe load based on what seems reasonable from other loads, and go even safer because of the primer change. Chrony the loads, plug into graph, extrapolate the load-velocity curve, and use that to determine where a "safe max" might be and work up to that. And I'll definitely share results!! I would imagine any JRC 40S&W owner would want this load data after I find what works well. Whatever powder they use would likely be a fast or intermediate pistol powder, such as WST. Probably the same powder used in 9mm 147gr loads, is my guess.

[popper]

boolit 180gr+ so the velocity is below 1150fps + LRP = glad you don't go to my range. Not WST.

[brown bass hunter]

I know you may not be looking for a truncated cone boolit, but my JRC in 40 loves the Lee 180 TC design. Feeds smooth without issue.

[Forgetful]

I know you may not be looking for a truncated cone boolit, but my JRC in 40 loves the Lee 180 TC design. Feeds smooth without issue.

I understand why the 10mm/40 standard is TC, but the RN have better BC's and some of them are still 180gr but shorter OAL than a TC.