45acp 185gn rnfp oal help

K

kbialick

Inactive
Hi I've always loaded 200 lswc at 1.250 oal
I recently got 1000 185gn rnfp plated rounds from Rocky Mountain reloading
I have read a couple different form threads on minimum of oaL but no real definite answers I've tried subtracting the bullet length from the 200 to the 185 to keep same pressure but that gives me a oal of 1.090 and that can't be right (200 is .647 and 185 is .488) I tried dummy loading to 1.190 and it physical looks good but I don't know how that difference would affect pressure with load data since it's such a smaller bullet in length
 
kbialick wrote:
1.090 and that can't be right...
Click to expand...

Why not?

It gives you precisely the same case capacity as the 200 gr load.

...1.190 and it physical looks good but I don't know how that difference would affect pressure...
Click to expand...

1.190 increases case capacity and that will almost certainly LOWER peak pressure - although probably not by much.
 
Well I did hear back from Rmr just now and they said to use Hodges's data for jswc and that stated .135 .... the .090 seemed like it was seated too deep like it was into the curve of the bullet and I agree .190 would def lower pressure which is why I was curious what others used
 
I think you've kind of got yourself wrapped around the axle a little, and I suggest a re-group.

I've tried subtracting the bullet length from the 200 to the 185 to keep same pressure
Click to expand...

I get what you're trying to do there. And on paper it would seem like a good approach. Doing the math and inserting the lighter bullet accordingly to achieve the same internal case volume seems like a logical approach. But because the bullets are different weights, doing so won't keep the "same pressure." But that's mostly outside the scope of the real issue: finding the correct OAL for your 185 grain bullet. And while we're outside scope: I set my 200 LSWC's to an OAL of 1.240" - so your 1.250" is right in the ballpark.

I digress . . .

That 185 grain bullet is an interesting specimen. Can't say I've ever seen anything quite like it. And to be certain, it bears no resemblance to a 200gn LSWC. Which is another reason why it's time for a re-group.

Determine your OAL by "plunk test" - the only thing that should determine OAL (assuming magazine clearance; and enough bullet gripping the case). If it's load data you need, there's lots of sources available. And if there isn't by some odd chance, it would be okay to start with your 200 LSWC recipe and work up from there - which would depend on your non-stated purpose for this ammo.

OAL should not be set to achieve a certain internal case volume. For that reason, you're barking up the wrong tree. Set OAL by plunk. Then set charge weight by load workup for your given purpose.

Which I'm curious: What is your given purpose for this ammo? I do have some 185 grain load workup data that could be used as a guideline.

It would also be good to know your chosen propellant; your charge weight (for the 200 LSWC's); and the firearm to discharge them (most importantly, barrel length).

Let's work on getting you into some good 185 grain ammo ;).
 
thank you nick!

I'm using these load for very soft shooting for practice and steel challenges

I'm shooting a range officer 1911 5"

my 200gn lswc i was shooting clays with 3.6 with a col of 1.250 and X69 on the crimp.(i forget the full crimp number off hand only pay attention to last two number on calipers anyway)
i started with the same numbers for the 185gn but with the RMR recommendation of 1.135 i went with 1.145 instead because i wasn't sure if hedges website was referring to there col and what i should be using or what the minimum col should be.
i was able to fire them and they were incredibly soft but had a lot of fte even with my 14lb spring installed so i think i might need to bump powder up to 3.8
 
Would consider paying careful attention to Nick's "and enough bullet gripping the case". A 200 lrnfp has minimal bearing surface, a 185 has even less. Unlike a 185 target wad cutter, or semi wadcutter.

Might want to load up a dummy round, and see what happens when ya release the slide on it.
 
Short bullets are to reload for. I would probably load to 5 different oal's at min charge weight. See which one feeds and has best accuracy. I say this because min published load usually is an accuracy node.

I would use the plunk test to find the longest oal. I would look through load manuals for the shortest.....that is probably 1.190-1.200".

Then shoot them and see what is most accurate and functions.
 
i was able to fire them and they were incredibly soft but had a lot of fte even with my 14lb spring installed so i think i might need to bump powder up to 3.8
Click to expand...

Since OAL doesn't seem to be an issue at this point, it should be fine to stick with your current OAL of 1.145" (although my gut tells me that the 1.135" may be preferred) and see how they perform at the 3.8 grain charge weight. Forthcoming adjustments may be in order, but I think your approach is sound now.

As Zeke alluded, with that short 185, I still have concerns about how much bullet is gripping the case; or, how much case is gripping the bullet :p.

In terms of ogive (nose shape), the closest thing I load is a 200gn PFP from X-treme. I load them to 1.175" - but they're pointier than your 185's (thus lending itself to a slightly longer OAL). So from a cycling standpoint, I think you're just fine at 1.145". I'm only concerned about the bullet seat/grip thing. But I don't load a lot of 185's, so I don't want to overstep my experience here. If they're sufficiently gripping the case and staying put, then they're sufficiently gripping the case and staying put.
 
You are right around the starting load for Clays.
I would not worry about case volume, seating, pressure interactions, you are making powderpuffs anyhow.

The main thing is an OAL that will feed that stubby bullet and enough bullet pull that it does not set back while feeding.
 
You must log in or register to reply here.
Back
Top