.40 OAL ??

pt4u2nv · November 9, 2009, 03:03 PM

Just started relaoding again after about a 5 year hiatis so I may be a little niave for awhile. I never reloaded .40 SW before and have a question about the importance of the OAL in a .40 cal semi-automatic. It seems as though once I got my bullet seating die where I wanted it (1.120" with 180 gr GDHP) ... I started getting what I considered drastic differences in the OAL. I got anywhere from 1.15 upwards to 1.30. I changed the bullet seating stem out for the larger seat thinking maybe the bullet was not seating uniformly but that made no difference. I am using the RCBS Carbide 40/10 MM die set. Is it possible the bullets are that much different at the nose that my readings are picking up the inconsistencies of the bullet? Will these differences be detrimental as far as pressures go with the .40, kind of concerns me with all the hype on the sensitivity of the .40 I have been reading about.

stacks04 · November 9, 2009, 03:42 PM

what kind of press?

NWPilgrim · November 9, 2009, 04:14 PM

Most .40 bullets are hollow point or truncated cone/flat point, so the seating stem should have a fairly flat surface against the bullet tip.

Whenever I get any noticeable variance in seating depth, I make sure my load is appropriate for the shortest OAL. If your load data is for 1.200" and you are getting some at 1.150 then personally I would not load to max charges, maybe load up to 0.5 gr less than listed max (depending o powder, but assuming about 5.0 gr of something). Or, try to find a data table with loads listed for OAL of 1.150". Lyman often has a wide variety of OAL in its manuals, whereas others test all loads at the same OAL.

If you are loading cast lead bullets the variance may also be from a build up of bullet lube in the seating die. I blast my dies with brake cleaner (non-chlorinated) and scrub with a cotton swab before each loading session.

If all else fails, call RCBS and see what they advise. I am not sure whether that amount of variance would be much of a factor in terms of pressure, but there is no reason for that much and that would just bug me until I fixed it.

pt4u2nv · November 9, 2009, 08:11 PM

Quote:

what kind of press?

RCBS Piggy Back on a Rock Chucker Press

castnblast · November 9, 2009, 08:30 PM

I have noticed on HP's that subtle diffences in how hard you pull the handle that it affects the seat depth. I noticed when I start really booking it, I get indentions on the bullet, and deeper seats, especially with my 135gr HP's.

bullspotter · November 9, 2009, 08:31 PM

Had the same problems when i started loading 40, part of the problem was the seat and crimp die, Where i like my crimp, was a bit to tight and caused some problems, so i backed the crimp off , now ill load them up, then turn the crimp where i want it and run them though with the seat stem out of the die, made a drastic improvement on COL, also if you are loading mixed brass, you may want to sort by head stamps, and load them in groups, some brass sidewalls are thicker then others, causing a tighter crimp. Re adjusting for each HS, Not saying this is the best way to do things, and im sure lots of guys crimp and seat all in one, with mixxed brass just fine, but doing this took away all my COL issues, and i have great shooting ammo.

isanchez2008 · November 9, 2009, 11:15 PM

I have loaded GDHPs for my .40 and had similar issues. Can't say for sure but the little nubs of lead that barely stick up above the mouth of the hollowpoint may be the culprit. I don't seat and crimp at the same time. They all functioned and fired fine but I did start loading them at 1.125". Still function fine. I like the Hornady XTP's in 180gr. No lead protruding over the top.

DWARREN123 · November 10, 2009, 12:07 AM

For me the OAL changes with the crimp and how much I bell the cases. I have found that as long as they fit the mag and chamber, don't cause any problems they work fine.

freakshow10mm · November 10, 2009, 12:24 AM

Pressure anomalies in the brass and bullet when the bullet is seated can be a culprit.

Shoney · November 10, 2009, 12:30 AM

To measure that thre is consistency in the OAL on a hollow point, you need to use a comparator. The comparitor measures the "relative" oal at the ojive of the bullet, not at the uneven jaged edges of the hollow point.

pt4u2nv · November 10, 2009, 08:42 AM

Thanks guys for all the great info. Just for the record I am using brand new Winchester brass only so that is proably not the issue. It appears from all of your info that the configuration of the bullet nose probably is what is giving me the inconsistant readings I sort of assumed this from the beginning so again, thanks for all your help.I also like the idea of crimping and seating at different stages, I will try that and see what the results are.

enstorm · November 10, 2009, 04:49 PM

I don't use speer for these types of issues. For 180 g hp in 40 try Golden Sabres, XTPs and Montana Gold

Shoney · November 10, 2009, 05:17 PM

If it's brand new brass, and you didn't size it, the bullet may be loose in a few pieces of brass. That could contribute to your problem.

pt4u2nv · November 11, 2009, 07:35 AM

Quote:

If it's brand new brass, and you didn't size it, the bullet may be loose in a few pieces of brass. That could contribute to your problem

I did run the new brass thru the sizing die since it was the first stage on my press so that should not have been an issue . Thanks again for your help . I will try a few things different and see if the problem goes away. I do have XTP's to try so I am anxious to see if they are a problem too.

pt4u2nv · November 12, 2009, 09:49 AM

Quote:

Had the same problems when i started loading 40, part of the problem was the seat and crimp die, Where i like my crimp, was a bit to tight and caused some problems, so i backed the crimp off , now ill load them up, then turn the crimp where i want it and run them though with the seat stem out of the die, made a drastic improvement on COL, also if you are loading mixed brass, you may want to sort by head stamps, and load them in groups, some brass sidewalls are thicker then others, causing a tighter crimp. Re adjusting for each HS, Not saying this is the best way to do things, and im sure lots of guys crimp and seat all in one, with mixxed brass just fine, but doing this took away all my COL issues, and i have great shooting ammo.

OK, Update time. I had time last night to run some more shells thru the press and did what bullspotter suggested and seated the bullets 1st then crimped them in a separate operation. It worked great ! The bullet seating stayed extremely consistant with variations around .001-.003. Thanks

stacks04 · November 12, 2009, 03:22 PM

the point of my question was handle pull being inconsistent. it was said since my post so i wont restate it.
i also had a big problem with a rcbs .40 die set. it was sizing the cases wrong.

November 9, 2009, 03:03 PM	#1
pt4u2nv Junior Member Join Date: November 9, 2009 Posts: 6	.40 OAL ?? Just started relaoding again after about a 5 year hiatis so I may be a little niave for awhile. I never reloaded .40 SW before and have a question about the importance of the OAL in a .40 cal semi-automatic. It seems as though once I got my bullet seating die where I wanted it (1.120" with 180 gr GDHP) ... I started getting what I considered drastic differences in the OAL. I got anywhere from 1.15 upwards to 1.30. I changed the bullet seating stem out for the larger seat thinking maybe the bullet was not seating uniformly but that made no difference. I am using the RCBS Carbide 40/10 MM die set. Is it possible the bullets are that much different at the nose that my readings are picking up the inconsistencies of the bullet? Will these differences be detrimental as far as pressures go with the .40, kind of concerns me with all the hype on the sensitivity of the .40 I have been reading about.

November 9, 2009, 04:14 PM	#3
NWPilgrim Senior Member Join Date: September 29, 2008 Location: Oregon Posts: 2,346	Most .40 bullets are hollow point or truncated cone/flat point, so the seating stem should have a fairly flat surface against the bullet tip. Whenever I get any noticeable variance in seating depth, I make sure my load is appropriate for the shortest OAL. If your load data is for 1.200" and you are getting some at 1.150 then personally I would not load to max charges, maybe load up to 0.5 gr less than listed max (depending o powder, but assuming about 5.0 gr of something). Or, try to find a data table with loads listed for OAL of 1.150". Lyman often has a wide variety of OAL in its manuals, whereas others test all loads at the same OAL. If you are loading cast lead bullets the variance may also be from a build up of bullet lube in the seating die. I blast my dies with brake cleaner (non-chlorinated) and scrub with a cotton swab before each loading session. If all else fails, call RCBS and see what they advise. I am not sure whether that amount of variance would be much of a factor in terms of pressure, but there is no reason for that much and that would just bug me until I fixed it. __________________ "The ultimate authority ... resides in the people alone. ... The advantage of being armed, which the Americans possess over the people of almost every other nation ... forms a barrier against the enterprises of ambition." - James Madison

November 9, 2009, 08:30 PM	#5
castnblast Senior Member Join Date: July 2, 2006 Location: Corpus Christi TX Posts: 1,148	I have noticed on HP's that subtle diffences in how hard you pull the handle that it affects the seat depth. I noticed when I start really booking it, I get indentions on the bullet, and deeper seats, especially with my 135gr HP's. __________________ VEGETARIAN...old indian word for bad hunter

November 10, 2009, 12:07 AM	#8
DWARREN123 Senior Member Join Date: January 22, 2006 Location: BETWEEN TN & KY Posts: 1,758	For me the OAL changes with the crimp and how much I bell the cases. I have found that as long as they fit the mag and chamber, don't cause any problems they work fine. __________________ Have a nice day!

November 10, 2009, 12:30 AM	#10
Shoney Senior Member Join Date: February 21, 2002 Location: Transplanted from Montana Posts: 2,311	To measure that thre is consistency in the OAL on a hollow point, you need to use a comparator. The comparitor measures the "relative" oal at the ojive of the bullet, not at the uneven jaged edges of the hollow point. __________________ I pledge allegiance to the Flag - - -, and to the Republic for which it stands….Our Forefathers were brilliant for giving us a Republic, not a democracy! Do you know the difference??? and WHY?http://www.wallbuilders.com/LIBissue...les.asp?id=111

November 9, 2009, 03:42 PM	#2
stacks04 Member Join Date: February 27, 2009 Posts: 62	what kind of press?

November 9, 2009, 08:31 PM	#6
bullspotter Senior Member Join Date: November 2, 2008 Location: Montana Posts: 308	Had the same problems when i started loading 40, part of the problem was the seat and crimp die, Where i like my crimp, was a bit to tight and caused some problems, so i backed the crimp off , now ill load them up, then turn the crimp where i want it and run them though with the seat stem out of the die, made a drastic improvement on COL, also if you are loading mixed brass, you may want to sort by head stamps, and load them in groups, some brass sidewalls are thicker then others, causing a tighter crimp. Re adjusting for each HS, Not saying this is the best way to do things, and im sure lots of guys crimp and seat all in one, with mixxed brass just fine, but doing this took away all my COL issues, and i have great shooting ammo.

November 9, 2009, 11:15 PM	#7
isanchez2008 Senior Member Join Date: October 13, 2008 Location: WA Posts: 344	I have loaded GDHPs for my .40 and had similar issues. Can't say for sure but the little nubs of lead that barely stick up above the mouth of the hollowpoint may be the culprit. I don't seat and crimp at the same time. They all functioned and fired fine but I did start loading them at 1.125". Still function fine. I like the Hornady XTP's in 180gr. No lead protruding over the top.

November 10, 2009, 12:24 AM	#9
freakshow10mm Junior member Join Date: January 23, 2008 Location: MI Posts: 1,398	Pressure anomalies in the brass and bullet when the bullet is seated can be a culprit.

November 10, 2009, 08:42 AM	#11
pt4u2nv Junior Member Join Date: November 9, 2009 Posts: 6	Thanks guys for all the great info. Just for the record I am using brand new Winchester brass only so that is proably not the issue. It appears from all of your info that the configuration of the bullet nose probably is what is giving me the inconsistant readings I sort of assumed this from the beginning so again, thanks for all your help.I also like the idea of crimping and seating at different stages, I will try that and see what the results are.

November 10, 2009, 04:49 PM	#12
enstorm Senior Member Join Date: August 11, 2005 Posts: 217	I don't use speer for these types of issues. For 180 g hp in 40 try Golden Sabres, XTPs and Montana Gold

November 10, 2009, 05:17 PM	#13
Shoney Senior Member Join Date: February 21, 2002 Location: Transplanted from Montana Posts: 2,311	If it's brand new brass, and you didn't size it, the bullet may be loose in a few pieces of brass. That could contribute to your problem. __________________ I pledge allegiance to the Flag - - -, and to the Republic for which it stands….Our Forefathers were brilliant for giving us a Republic, not a democracy! Do you know the difference??? and WHY?http://www.wallbuilders.com/LIBissue...les.asp?id=111

November 12, 2009, 03:22 PM	#16
stacks04 Member Join Date: February 27, 2009 Posts: 62	the point of my question was handle pull being inconsistent. it was said since my post so i wont restate it. i also had a big problem with a rcbs .40 die set. it was sizing the cases wrong.