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P320 9mm reloading questions


Sig0431

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I consider myself to still be "new" into the world of reloading. While I thought I had my Limited 9mm minor loads down for my P320 after reading many posts on here I have started developing questions. If anyone can help me out with any of the below it would be greatly appreciated. I have been searching the site for my answers but finding this information specific to the P320 is a little difficult. Please keep in mind that I am a Marine so at times I need things broken down "Barney Style" to understand haha.

 

1. OAL. I understand that every barrel can have slightly different measurements. I keep hearing people refer to the "plink" or "plunk test" but I have seen so many different descriptions on this "test". Can someone explain how this is done to determine your OAL or if there is a more beneficial way I should do this? I have seen people post OAL's for the P320 from 1.100 to 1.135

 

2. 1911 recoil springs / Load Data. Over the next few weeks I want to test loads and spring set ups using the following items:

 

Powder: TiteGroup / Prima V

Bullets: 124g / 135g / 147g (ACME, Blue Bullets and BBI). 

Springs: 14lb / 15lb / 16lb

 

Can someone recommend loads and the 1911 spring? If I should consider additional spring weights I have no issue ordering them. Lastly I am not to focused on the 147g bullets, I purchased those primarily to created dummy rounds for dry firing but will have about 100 left over. In the past I have been loading 3.2g-3.6g TiteGroup with 124g JHP with various OAL's. I have read the loading post here for the P320 but there is maybe 2 loads listed on there that apply to my options on hand.

 

3. Factory Crimp. I have used the factory crimp die in the past for my JHP but have heard mixed input from posts on this site and bullet manufactures websites, some saying to never crimp coated bullets like BBI and some saying to crimp but only slightly. As I mentioned above I have seen many posts and read them but I would like to hear some input from P320 owners.

 

4. Bullet effects on load. With shooting coated bullets like BBI, do these bullets affect your loads compared to jacketed bullets? I understand the PF affects but I have seen posts about the different coated bullets (with same weight) requiring different OAL's or powder amount. It almost seems like there is specific load data for the bullets. Is this true or am I just reading stuff wrong? 

 

If anyone would also find this information beneficial I will be more than happy to post images and after action reports about the information provided by members. I really wish one of you lived in Yuma so that I could have a mentor to help me un-F*** myself haha. Thank you all in advance for your help!

Edited by Sig0431
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I can try to address some of your points based on my own experience.

 

1. As I understand it, a plunk test is just dropping the loaded round into your barrel to see if the case head sits flush with the rear of the barrel hood.  I have determined the OAL of my 226, X5, and PPQ by the following unscientific method:

  • Using a fired (not resized) case, place a bullet in it only as far as necessary to hold it in place.  It's usually loose enough in the case that it can slide in and out without too much difficulty. 
  • Push the case/bullet into the chamber until it's seated.  The rifling will engage the bullet and push it back into the case.
  • Remove the case and measure the OAL of the round.
  • Repeat a few times to get an average, then subtract a few thousandths and use that as your maximum OAL.

Of course, that OAL also has to fit in your magazines and function in the gun.  I used to load to ~1.13 for my Sigs, but the Walther has a tighter chamber and I had to go down to ~1.10.  I've essentially given up trying to denote OAL to the thousandth.  Between tolerances in my press and bullet coating thickness at the tip, I always get a range of ~0.005" when measured across 10% of every batch.

 

2.  Can't help you there, as I don't have a 320 (yet).

 

3.  I've always crimped just enough to remove the bell from the case mouth.  You can check to see if you are crimping your coated bullets too much by pulling one after you load it and examining the coating.  If it's stripped off, you're over-crimping.

 

4.  Coated bullets will require less powder than jacketed to achieve the same velocity.  If looking for a starting load, use lead bullet data, not jacketed data.  Different bullet profiles can affect the OAL, as one bullet can have the shoulder farther forward or rearward than another, which would contact the rifling at different distances out from the case mouth.  If you are loading right to the maximum OAL your chamber will allow, this could be more of a problem.  If you load to typical factory OALs (~1.10), probably not.  I have not seen specific load data for specific coated bullets.  It's more of a trial and error process.

Edited by JAFO
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@JAFO For the plunk test when you say "Push the case/bullet into the chamber until it's seated" is that until the case will no longer go forward? I am aware of the lip inside the barrel for the case I just don't want to assume anything and ensure I am doing this right. Thank you so much for the insight, I will try the plunk test as you have described it once I get home and post what I have found. I will do this test for each type of bullet I have and see what you all think.

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Every bullet has a different profile. Something that is very long tapered and pointy can be loaded much longer than a bullet which is short and fat. So each individual barrel and bullet combination needs a plunk & spin conducted:

 

You can load some 147gr bullets to 1.130+ in a CZ with it's notoriously short chamber. With others ... you're stuck down as low as 1.090 due to the shape.

 

Plunk test is simply:

1. Size a case, seat a bullet into it, and then crimp it. Without crimping it, the flared mouth won't chamber.

2. Drop it into your barrel and make sure it spins freely. If you can't spin it effortlessly, the bullet is stuck in the rifling and you're loaded too long.

3. Shorten that dummy round or load a new one shorter, and repeat.

 

That's it. It's not rocket science.

 

Note also: sometimes you can load all the way out to perhaps 1.150 on a certain gun. My Glock 34 would let me, with their generous chambers. But the most accurate load for that gun with a 124gr Bullet was generally around 1.125"

 

The plunk test is to figure out how long you can load. From there, you need to work on ammo shorter than this to tune your ammo to your particular gun.

 

Edited by MemphisMechanic
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26 minutes ago, Sig0431 said:

@JAFO For the plunk test when you say "Push the case/bullet into the chamber until it's seated" is that until the case will no longer go forward? I am aware of the lip inside the barrel for the case I just don't want to assume anything and ensure I am doing this right. Thank you so much for the insight, I will try the plunk test as you have described it once I get home and post what I have found. I will do this test for each type of bullet I have and see what you all think.

 

Yes.  If your fired cases won't allow a bullet to slide in easily, you will have to do as MephisMechanic described and actually bell, seat, and crimp the bullet into the case.

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I do that anyway, and simply push the bullet further back into the crimped case over and over until I find my max OAL for that gun and that bullet.

 

You don't really want to do that with live ammo for a variety of reasons, but with dummy it won't hurt anything.

 

Then it goes into my dryfire dummy round collection. ;) 

Edited by MemphisMechanic
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So I just tried the plunk test and it was harder than I thought. The bullet seemed to pull out of the brass a little as I tried to remove the round from the case. I ended up backing off my seating die and slowly adjusting it until the round would seat and function. Below pictures show my results. The OAL seems longer than any I have seen posted yet it has no issues chambering, the firing pin will function and it will eject with no hang ups at all. Does this seem normal? The bullet is a 147g ACME

IMG_20170320_185354.jpg

IMG_20170320_185354_2.jpg

Edited by Sig0431
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3 minutes ago, Foxtrotx1 said:

Quick question. Anyone else reloading for the P320 run into the issue where not crimping after flaring is allowing rounds to engage the slide lock after each shot? sounds crazy, I know. 

Sadly I don't have a direct answer for you. What powder, grains bullets etc are you loading? Also do you have the factory recoil spring or a 1911 style spring? Lastly did you take the trigger assembly apart recentally? Could be that tour slide lock level spring is out of place. Just throwing ideas out there.

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I did take it down recently. I installed the grey guns trigger, never thought to check that. I recently had it milled for an RDS and it always wears a threaded barrel and a can. Worked fine until last trip. I did break it down in the field though. 

 

I did break it down right before shooting it (removed modular FCG to show freind) and hastily resembled it. problems started after that. 

Edited by Foxtrotx1
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So after many rounds using different powders, bullet weights, springs etc. I have begun to fall in love with 135gr, 3.2gr Prima V, and 14lb spring @1.148. I almost want to try a 13 and 12lb spring but this load is shooting so flat as it is I don't think I need to. I still need to get my hands on a crono to confirm the PF with this load but I am pretty sure It meets PF with some room to spare.

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  • 2 months later...

I shoot BBI 125gr loaded with 3.6gr of titegroup with a COAL of 1.100". Using a 15# 1911 spring. It feeds perfectly and is very flat and sights track very well. Makes 130PF confirmed at several major matches. 

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  • 2 weeks later...

 

I am curious what you folks are currently loading for the new P320 X-Five. I will be loading primarily 124 JHP with either TG or CFE Pistol powder. I was planning on trying an OAL somewhere between 1.100 and 1.135 depending on actual velocity & accuracy. Any recommendations from current X-Five owners?

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