9mm reloading questions

RayM · January 4, 2015, 08:23 PM

Following my books reloading data,
I have loaded 25 each ranging from starting load of 4.0
To 4.3 for the xtp 115 hp. C.O.L. 1.090.
My question is this. After i decide which load performs
Better in my berretta 92. Is headspacing the 9mm
Nessasary for improved accuracy????

hornetguy · January 4, 2015, 09:01 PM

First of all, welcome to the forum...

Your question has me puzzled. The only "headspacing" that I know about is what the gun manufacturer does when building the firearm. Headspace is the distance between the face of the bolt and the headspacing point, which varies from cartridge to cartridge. On bottlenecked cartridges, it is usually the datum line of the cartridge shoulder. On rimmed cartridges, it is the rim of the cartridge. On straight walled rimless cartridges, such as the 9mm, it is the mouth of the case.
A known, correct length gauge is inserted into the chamber, and the bolt is closed on it. If the bolt closes on the "go" gauge, that is good, but it's only half of it. A "no-go" gauge is then inserted in the chamber, and they attempt to close the bolt. It should not close on the "no-go" gauge. This gives the builder the information that the firearm is correctly headspaced.
As for the average shooter, adjusting the headspace should never be necessary, or even possible.

Can you clarify your question, or did my oversimplified response help you in any way?

RayM · January 4, 2015, 09:16 PM

Yes and no.
Let me try to explain better.
My .243 rounds were head spaced for greater accuracy. I used
Bench rest dies for exact seating depth.
Its my understanding that 9mm brass does not need trimming
Like rifle brass. What i was wondering, would it be necessary
Or need to increse the accuracy of the 9mm round.

skizzums · January 4, 2015, 09:21 PM

I assume your talking about getting out to max oal to get closer to the lands. yes, it would probably help accuracy, but I don't think to the point any of us mortals would notice w/o beig strapped into a ransom rest. if your shooting a semi auto, strive for the max OAL that you gun cycles reliably. you don't want a huge bullet jump to get to the rifling, but I have never noticed a longer oal giving me better accuracy, not saying it doesn't, just not noticeable to me

also, this forum has a reloading section that has a lot more educated handloaders that could help you out

saleen322 · January 4, 2015, 09:23 PM

A rimless case, like the 9mm, headspaces off the case mouth. This is why the correct seating die for a 9mm is a taper crimp die instead of a roll crimp die like a 38 Special and like rounds would have. That said, yes making sure your brass and taper crimp setting on your die is correct for the headspace in your Beretta will help accuracy.

RayM · January 4, 2015, 09:30 PM

Thank you very much. I was not sure if i needed to or not.
But i will play with C.O.L. to see. Thanks again

RayM · January 4, 2015, 09:38 PM

I do have a tapered crimp die. I always use one for consistent
Pressures and uniformity.
It has helped greatly on my accuracy.
Ill try playing with C.O.L. and see how that works.
Thanks for all the advice. Ill post my results after testing.

Worc · January 4, 2015, 10:13 PM

I think the term you are looking for is "Freebore". This is the distance from the bullet ogive to the rifling lands. With rifles some are more accurate with less free bore and some with more. Depends on the rifle and cartridge combination.

I've not heard of changing it for accuracy in the 9mm though. The COL on the 9mm usually has to do with pressure changes along with the other loading variables.

skizzums · January 4, 2015, 10:24 PM

I do believe the same goes for pistol as rifles, with the less bullet jump being most preferable, I don't think the results can be extreme as with rifles since we are rarely going for sub-moa groups with 9mm pistols. but I do hear accuracy issues with extreme jump in revolvers when shooting stepped down cartridges, like 38spl in a 357 chamber etc. play with it, but be scientific, as I think it will be very hard to notice any variances. if this is something you end up doing, let us know your results and make sure your rounds are passing the "plunk" test as you start playing with longer oal's, most guns will not fire out of battery, but things happen

hartcreek · January 5, 2015, 12:56 AM

Some of us with experience do not use the taper crimp. I am one of them. The trick with any cartridge that headspaces on the case mouth is getting enough crimp to hold the bullet and yet still be able to headspace on the case mouth. Fortunately for me I started loading 9mm with an old set of non carbide RCBS dies with a factory crimp die.

I have tried using the taper crimp...it did not work for me.

January 4, 2015, 08:23 PM	#1
RayM Junior Member Join Date: January 4, 2015 Posts: 4	9mm reloading questions Following my books reloading data, I have loaded 25 each ranging from starting load of 4.0 To 4.3 for the xtp 115 hp. C.O.L. 1.090. My question is this. After i decide which load performs Better in my berretta 92. Is headspacing the 9mm Nessasary for improved accuracy????

January 4, 2015, 09:01 PM	#2
hornetguy Senior Member Join Date: January 14, 2011 Location: on the north side of DFW Posts: 970	First of all, welcome to the forum... Your question has me puzzled. The only "headspacing" that I know about is what the gun manufacturer does when building the firearm. Headspace is the distance between the face of the bolt and the headspacing point, which varies from cartridge to cartridge. On bottlenecked cartridges, it is usually the datum line of the cartridge shoulder. On rimmed cartridges, it is the rim of the cartridge. On straight walled rimless cartridges, such as the 9mm, it is the mouth of the case. A known, correct length gauge is inserted into the chamber, and the bolt is closed on it. If the bolt closes on the "go" gauge, that is good, but it's only half of it. A "no-go" gauge is then inserted in the chamber, and they attempt to close the bolt. It should not close on the "no-go" gauge. This gives the builder the information that the firearm is correctly headspaced. As for the average shooter, adjusting the headspace should never be necessary, or even possible. Can you clarify your question, or did my oversimplified response help you in any way?

January 4, 2015, 09:16 PM	#3
RayM Junior Member Join Date: January 4, 2015 Posts: 4	Yes and no. Let me try to explain better. My .243 rounds were head spaced for greater accuracy. I used Bench rest dies for exact seating depth. Its my understanding that 9mm brass does not need trimming Like rifle brass. What i was wondering, would it be necessary Or need to increse the accuracy of the 9mm round.

January 4, 2015, 09:21 PM	#4
skizzums Senior Member Join Date: July 1, 2013 Location: Douglasville, Ga Posts: 4,615	I assume your talking about getting out to max oal to get closer to the lands. yes, it would probably help accuracy, but I don't think to the point any of us mortals would notice w/o beig strapped into a ransom rest. if your shooting a semi auto, strive for the max OAL that you gun cycles reliably. you don't want a huge bullet jump to get to the rifling, but I have never noticed a longer oal giving me better accuracy, not saying it doesn't, just not noticeable to me also, this forum has a reloading section that has a lot more educated handloaders that could help you out

January 4, 2015, 09:23 PM	#5
saleen322 Senior Member Join Date: March 8, 2010 Posts: 779	A rimless case, like the 9mm, headspaces off the case mouth. This is why the correct seating die for a 9mm is a taper crimp die instead of a roll crimp die like a 38 Special and like rounds would have. That said, yes making sure your brass and taper crimp setting on your die is correct for the headspace in your Beretta will help accuracy.

January 4, 2015, 09:30 PM	#6
RayM Junior Member Join Date: January 4, 2015 Posts: 4	Thank you very much. I was not sure if i needed to or not. But i will play with C.O.L. to see. Thanks again

January 4, 2015, 09:38 PM	#7
RayM Junior Member Join Date: January 4, 2015 Posts: 4	I do have a tapered crimp die. I always use one for consistent Pressures and uniformity. It has helped greatly on my accuracy. Ill try playing with C.O.L. and see how that works. Thanks for all the advice. Ill post my results after testing.

January 4, 2015, 10:13 PM	#8
Worc Senior Member Join Date: July 24, 2013 Location: Michigan Posts: 641	I think the term you are looking for is "Freebore". This is the distance from the bullet ogive to the rifling lands. With rifles some are more accurate with less free bore and some with more. Depends on the rifle and cartridge combination. I've not heard of changing it for accuracy in the 9mm though. The COL on the 9mm usually has to do with pressure changes along with the other loading variables.

January 4, 2015, 10:24 PM	#9
skizzums Senior Member Join Date: July 1, 2013 Location: Douglasville, Ga Posts: 4,615	I do believe the same goes for pistol as rifles, with the less bullet jump being most preferable, I don't think the results can be extreme as with rifles since we are rarely going for sub-moa groups with 9mm pistols. but I do hear accuracy issues with extreme jump in revolvers when shooting stepped down cartridges, like 38spl in a 357 chamber etc. play with it, but be scientific, as I think it will be very hard to notice any variances. if this is something you end up doing, let us know your results and make sure your rounds are passing the "plunk" test as you start playing with longer oal's, most guns will not fire out of battery, but things happen

January 5, 2015, 12:56 AM	#10
hartcreek Junior member Join Date: April 22, 2014 Location: Washington Posts: 1,549	Some of us with experience do not use the taper crimp. I am one of them. The trick with any cartridge that headspaces on the case mouth is getting enough crimp to hold the bullet and yet still be able to headspace on the case mouth. Fortunately for me I started loading 9mm with an old set of non carbide RCBS dies with a factory crimp die. I have tried using the taper crimp...it did not work for me.