Plunk Test

[Drillbit]

Doing the Plunk test, I have found the point of touch for the bullet I'm using.  My question is, do I shoot it at that oal or go deeper.  In going deeper, will I find better accuracy?  

 

[shred]

You want to be shorter than touching the rifling with pistols-- 0.010" to 0.020" shorter as a goal works for me, assuming the mags are sympatico with that OAL.  There's no useful accuracy to be gained and every chance for a slightly dirty gun or slightly large bullet or slightly long round to ruin your day.

 

[Yeti]

Longer OAL typically feeds better (2011/1911) but this is all build based.  This can be very helpful for 40S&W and to a lesser degree 9mm.  Don't ask for problems stay at least 0.015" back from any contact.

MAX for 9x19 is 1.169" however IMO if you are longer than 1.150" you should really ask yourself why.  

[HesedTech]

16 hours ago, Drillbit said:

In going deeper, will I find better accuracy?  

Not in pistol rounds. In precision rifle the jump to the lands starts to count for very long shots. With pistol rounds as others have written the OAL may make your ammo feed more reliable. Accuracy is more effected by bullet profile, barrel, barrel fit, bullet diameter, velocity, ammo consistency, properly adjusted sights, and your finger. OAL changes won't be noticed.

[Farmer]

20 hours ago, Drillbit said:

In going deeper, will I find better accuracy?  

 

I generally seat -.015 off the lands but have two bullets, a 135 FMJRN and a 124 coated TC that I have to seat @ -.030 to settle down and shoot right. All depends on your gun but at least .015” is a good place to start. Also gives room for crud buildup. 

[Drillbit]

Thank you, gentleman. From the advice given so far, 0.015 sounds like a good start.   

Edited July 16 by Drillbit

[zzt]

On 7/16/2024 at 9:19 AM, Yeti said:

however IMO if you are longer than 1.150" you should really ask yourself why.  

 

To reduce pressure for 9mm major rounds.

[shred]

8 hours ago, zzt said:

 

To reduce pressure for 9mm major rounds.

and to keep them from chambering in unsuitable 9mm pistols by accident.

[zzt]

3 hours ago, shred said:

and to keep them from chambering in unsuitable 9mm pistols by accident.

 

Absolutely that.  I make it a practice to pick up every 9mm major round that hits the ground, even if it takes a while.  I usually catch the ejected round.  If I miss, I hunt it down.  Do not want to blow someone's gun up. 

[Yeti]

Did not realize we were discussing 9Major here.  Are we, Drillbit?

Edited July 20 by Yeti

[99mpower]

On 7/19/2024 at 10:06 PM, zzt said:

 

Absolutely that.  I make it a practice to pick up every 9mm major round that hits the ground, even if it takes a while.  I usually catch the ejected round.  If I miss, I hunt it down.  Do not want to blow someone's gun up. 

 

why would anyone be shooting live rounds they picked up off the ground? Thats just not very smart at all. 

[sharko]

I load at least .010" short of the lands, not for accuracy so much but to avoid jambs from OAL variance. Even if you don't get jambs rounds that are in the lands and ones that aren't will usually perform differently and can have significant pressure differences. 

 

I think zzt meant he picks up his own ammo, I do too, I would never pick up ammo that isn't mine or wasn't positive is mine.