View Full Version : 223 Shoulder bump?
If someone could explain this to me Barney style, I'd be thankful. I think I'm doing it right, but I have few questions.
Are you guys bumping the shoulder's back .003 from where it ends up after being fired? Or back to where it was before being fired? My hornady comparator shows my brass being bumped back to match factory new ammo, with none of it being bumped back more that .006 on the extreme end, if I remember correctly.
You should bump the shoulder of the fired case no less than .003" for a semi-auto rifle.
When a round is fired, it becomes what we call fireformed, which means it has expanded to the size of that specific chamber. Theoretically, you should bump the shoulder no less than .003" from that dimension for a semi-auto rifle. But not all brass expands the same; even like headstamp brass expand differently. I've measured as much as .004" difference from the same rifle, same brass, same day, etc. Some brass may expand .003", some .001", some not enough to measure. The easiest way to do it is take the brass casing that has expanded the most, and set your die to bump that one .003". The rest of the brass should be in-spec after sizing with that die setting.
Through trial and error, I know what size my brass needs to be to fit perfectly in each of my chambers. But you don't want the shoulder touching the chamber, you want it ~.003" away for a semi-auto. This is where the .003" shoulder bump comes in from the fired case.
This whole thing is what we call headspace, which is the distance measured from the part of the chamber that stops forward motion of the cartridge (the shoulder) to the face of the bolt. This is also the same dimension you measure with the Hornady gauge, but on the brass casing. Like I said above, whatever this measurement may be, you want the shoulder of the brass ~.003" away.
I'm not sure if this is what you are referring to with the Hornady camparator, but this is what I use to measure:
http://www.midwayusa.com/product/479704/hornady-lock-n-load-headspace-gage-5-bushing-set-with-comparator?cm_vc=ProductFinding
If you look at the SAAMI drawings, which can be found through Google, it will show you what size bushing you need to use to measure the headspace of the brass and it gives you a window of in-spec measurements. For .223Rem, you would use the .330 bushing to check if the brass is sized between 1.466" and 1.459".
I hope this helps.
Thank you! That is indeed the tool I was referring to.
I appreciate the recent "shoulder bumping" threads. I JUST bought a Sheridan gauge... no experience yet, figured the only way for me to learn is to start mashing test cases and measuring, just to find the "limits".
Can someone explain how the Sheridan (or Wilson) gauge is the same or different as that Hornady tool? Sounds like maybe the Sheridan is just a check, while the Hornady allows one to measure. Yeah?
I appreciate the recent "shoulder bumping" threads. I JUST bought a Sheridan gauge... no experience yet, figured the only way for me to learn is to start mashing test cases and measuring, just to find the "limits".
Can someone explain how the Sheridan (or Wilson) gauge is the same or different as that Hornady tool? Sounds like maybe the Sheridan is just a check, while the Hornady allows one to measure. Yeah?
Exactly, Sheridan gauges just check to see if the casing is withing a certain in-spec range. The Hornady Headspace gauges give you an actual measured number.
Exactly, Sheridan gauges just check to see if the casing is withing a certain in-spec range. The Hornady Headspace gauges give you an actual measured number.
In an ar15 where extraction is happening while there is residual pressure case guages are the best tool for the job. Especially when feeding multiple rifles. Thats why with the hornady guage you get inconsistent numbers. With the guage you size everything to fit the case guage and your good to go.
The hornady tool is a great tool, but it is not the best for checking headspace on brass fired from an ar15.
In an ar15 where extraction is happening while there is residual pressure case guages are the best tool for the job. Especially when feeding multiple rifles. Thats why with the hornady guage you get inconsistent numbers. With the guage you size everything to fit the case guage and your good to go.
The hornady tool is a great tool, but it is not the best for checking headspace on brass fired from an ar15.
I disagree, the Hornady gauge is the ONLY way to go if you want ammo custom tailored to YOUR specific rifle. Sheridan gauges don't measure anything for you. They only check the sized brass to make sure it's within the SAAMI spec window. Hell, most fired casings won't even fit in a sheridan gauge anyways due to the neck expansion. I for one, want all of my ammo to be EXACTLY the same, custom sized for my rifle(s). From headspace, powder charge, OAL, etc. ESPECIALLY match grade ammo. The more consistent and the more custom tailored your loads are to your rifle, the more consistent your results will be.
IMO, sheridan gauges are ok at best. They are fine for regular plinking/training/whatever ammo, but when you are trying to produce the most consistent ammo possible, they are the last thing I would choose. If you want ammo that is custom sized to your specific rifle, a headspace gauge is the ONLY way to go.
Just to clarify, I know why I get inconsistent fireformed measurements with the Hornady gauge. There's no getting around it due to the residual pressure as you mentioned, it's just part of the semi-auto life.
FWIW, I have a sheridan gauge for each caliber I own, but I haven't touched them since I got the Hornady gauge.
A case guage does not limit accuracy at all. Fire forming loads usings false shoulder can shoot sub half moa, and that brass is doing a hell of a lot more growing then the couple thousandths case guage sized brass is doing. Accuracy is about consistency.
Sizing by the measurement of the longest case is by no means tailoring the brass to your chamber. I have measured cases fired from the same ar that varied more than .003. So by bumping the longest one by .003 others might not be bumped back at all. That is not leading to consistent results. If your load is shooting sub moa with the brass sized the way you are, it will be sub moa sizing to a case guage.
In your post you said most cases will not fit in a case guage after firing. They are not supposed to. If you can not load match grade ammo using a case guage it is not the brass holding you back it is something wrong with your technique.
Exactly how much does brass usually grow when being fired from a 5.56 chamber. If I remember correctly, I bump the casings all back to match factory new ammo. Now I'm wondering if that wasn't too much, and if that isn't going to shorten the case life. Until I get a couple thousand reloads down range, I plan on reloading each case only twice.
Sizing the case more is going to shorten its life if you do not anneal it. You should still be able to get more than 2 loads safely. Using a case guage is helpful when feading multiple rifles. I have only used dillon case guages so incan not comment on the sherridan.
How much a case grows after being fired is going to be different. It is going to be rifle dependent. I will measure some and report back.
I just measured 3 once fired pieces and got 1.460, 1.463, and 1.465. The 3 pieces of factory loaded measured 1.458, 1.4575, and 1.457.
If you set your sizing die to bump the longest piece by .003, you have cases that are not even being bumped. That is just the first pieces I grabbed. I know from measuring in the past they can vary more than that. From my numbers if you bump back to factory length that less than .010. Dial that up on your calipers and see how much it really is.
Will it shorten case life? Yes. How hard is it to find 223/556 brass? It is one of the most abundant calibers out there. I know for me I will stick with the consistency the case guage provides.
Coal Dragger
05-24-14, 23:13
Case gauge is the only way to go for feeding a semi-auto, aside from that I'm having no problems making 1 MOA or better ammo after using a case gauge to set my full length resizing die. Plus I'm feeding two AR's and there's no way in hell I'm going to try to custom size brass for each one and keep two resizing dies in two tool heads, and separate all my brass. That is just freaking stupid.
Instead I'll enjoy shooting ammo I know is dimensionally correct for any in spec .223/5.56 chamber, and that shoots well in a good barrel. Chasing minute improvements in accuracy is not something that interests me all that much anyway, once I get a load that works 100% and gives me good accuracy I start making a bunch of it to shoot. The way I see it, I'm more likely to benefit from regular practice with ammo that is capable of .75-1.00 MOA (or even larger groups) than I am from shooting small quantities of test loads trying to shave .25-.50 MOA off of what is already a good load. It's much easier to crank out ammo from a set up press, powder measure etc than it is to change shit around every 5-10 rounds for an inconsequential improvement in accuracy.
I agree with everything you posted coal dragger. I have been reloading a lot longer than I have been loading for AR type rifles. When I started loading for the AR I realized trying for a minimum bump is pointless. You get so much variance in the fired case that a minimum bump leaves you with brass that is inconsistent and can cause problems. Using a case guage simplifies everything.
Those measurements are all from the same rifle. I have not shot anything but my mrp this year. So if a case can vary by that much in one chamber your just chasing your tale as far as sizing goes until you use a case guage. Unless you can shut off the gas system and have a straight pull bolt action all the measurements are meaningless.
Measure, schmeaure.
Any semi auto fired ammo should fit into a case guage. If I'm setting up a die for minimum bump for a bolt gun, I simply turn the die down until the bolt just closes nicely. I have none of these measurement devices.
I agree with everything you posted coal dragger. I have been reloading a lot longer than I have been loading for AR type rifles. When I started loading for the AR I realized trying for a minimum bump is pointless. You get so much variance in the fired case that a minimum bump leaves you with brass that is inconsistent and can cause problems. Using a case guage simplifies everything.
Those measurements are all from the same rifle. I have not shot anything but my mrp this year. So if a case can vary by that much in one chamber your just chasing your tale as far as sizing goes until you use a case guage. Unless you can shut off the gas system and have a straight pull bolt action all the measurements are meaningless.If I understand you correctly, about the best you can do for AR reloading is to adjust your dies to f-l resize until the case head is level with the upper step of the gauge (rather than the lower step or in-between).
Coal Dragger
05-25-14, 11:45
Pretty much. My fl resize die is set in between the high step and low step on a Dillon case gauge. The difference between the high and low step is tiny as it is.
If I understand you correctly, about the best you can do for AR reloading is to adjust your dies to f-l resize until the case head is level with the upper step of the gauge (rather than the lower step or in-between).
I adjust it to fall in between the steps on my dillon guage. A lot of factory ammo I have checked with my dillon case guage were even with the bottom step. Some factory falls in between the steps.
What I was getting at is that using head space guages like hornady are worthless for AR loading.
I adjust it to fall in between the steps on my dillon guage.
I agree. Flirting with the upper limit can leave you with ammo that won't chamber well.... and won't extract if you need to eject a live round. I learned this the hard way.
I only bump my shoulder back .002 each reloading but there is some other rules I set for myself. I'm a little anneal about sorting my brass and keep it sorted for each rifle and the times it has been reloaded. Fourth reloading is its last and it is either left laying on the ground or collected seperately for the scrap bin.
The reason for this is as the brass work hardens the bump will get inconsistent due to two reasons, work hardening or inconsistent lubing. I don't anneal AR brass (yet - been able to control the impulse) but each cycle through the press I check/measure. When the bump starts getting inconsistent due to work hardening I have no other choice but to add to the amount I'm bumping or anneal the brass to reduce the spring back. This process has worked well for me.
For brass from and unknown source, i.e. Widners or other surplus supplier it is FL sized to SAMMI or a case gauge and trimmed after firing in a perticular rifle it is kept with the rifle for its useful life.
I understand the work hardening. I even posted it will shorten case life, but unless im running hot loads I can get 5 loadings no problem.
If your only bumping your cases back by .002 how do you choose which case you use for the measurement. I measure cases fired from the same rifle and the measurements varied by mor than .004. So unless your cases are coming out consistently I do not see how you pick which case to size.
Measure more than 10 cases. I generally measure/record 40-60 cases each reloading until I feel comfortable with calling X my max length to work with. I generally get about a .004 spread in OAL with a few highs + .001-.002 and some lows that range from nothing to the top of the bell. An example would be Factory to + .001 (12), + .002 (8), + .003 (15), + .004 (21), + .005 (3), + .006 (1) and + .007 (0)
To get a max chamber size on a new rifle or bolt and barrel combination I load a virgin bag of Winchester factory brass with a previously established load. I also run a box of m193 and m855 as a factory known pressures and compare. If the chamber is pretty tight SAMMI to +.002 I usually get pretty consistent readings but at +.004 and larger it tends to take a couple of firings to find the true max and even then that is measuring the brass after spring back. I measure all the factory cases and about 20 -30 of the winchester cases. If it is all over the place perticularly with new brass that is fl sized to SAMMI -.004 to .006 coming out of the bag, I'll take the the longest length before it drastically drops off in averages, bump the winchester back .002 from that OAL and reload it. On the second firing I usually find a consistant max chamber length.
This isn't always the case though, my SCAR 17 (7.62 x 51) is in the SAAMI .007-8 range based on a 308 SAAMI chamber gauge. I've ran the same batch of hard military brass through it and I think I've finally found the bottom. The virgin brass is SAAMI - .004 to .006 so it has to grow .011 to .13 so I've been bumping it to SAAMI + .005 but it is starting to work harden and I'm starting to get inconsistant measurements so either I anneal it or add more to the bump. The rifle has not had a chambering or extraction problem since new with about 1k through it. Granted its not a benchmark test as I'm only pushing a 145 gr bullet at a midrange loading with ball powders (banging ammo).
Measure more than 10 cases. I generally measure/record 40-60 cases each reloading until I feel comfortable with calling X my max length to work with. I generally get about a .004 spread in OAL with a few highs + .001-.002 and some lows that range from nothing to the top of the bell. An example would be Factory to + .001 (12), + .002 (8), + .003 (15), + .004 (21), + .005 (3), + .006 (1) and + .007 (0)
To get a max chamber size on a new rifle or bolt and barrel combination I load a virgin bag of Winchester factory brass with a previously established load. I also run a box of m193 and m855 as a factory known pressures and compare. If the chamber is pretty tight SAMMI to +.002 I usually get pretty consistent readings but at +.004 and larger it tends to take a couple of firings to find the true max and even then that is measuring the brass after spring back. I measure all the factory cases and about 20 -30 of the winchester cases. If it is all over the place perticularly with new brass that is fl sized to SAMMI -.004 to .006 coming out of the bag, I'll take the the longest length before it drastically drops off in averages, bump the winchester back .002 from that OAL and reload it. On the second firing I usually find a consistant max chamber length.
This isn't always the case though, my SCAR 17 (7.62 x 51) is in the SAAMI .007-8 range based on a 308 SAAMI chamber gauge. I've ran the same batch of hard military brass through it and I think I've finally found the bottom. The virgin brass is SAAMI - .004 to .006 so it has to grow .011 to .13 so I've been bumping it to SAAMI + .005 but it is starting to work harden and I'm starting to get inconsistant measurements so either I anneal it or add more to the bump. The rifle has not had a chambering or extraction problem since new with about 1k through it. Granted its not a benchmark test as I'm only pushing a 145 gr bullet at a midrange loading with ball powders (banging ammo).
Thats a lot of work. That would drive me crazy but it must be working for you. I went through a time 2here I took similar steps. Now I just dont see the results being worth the effort.
Thats a lot of work. That would drive me crazy but it must be working for you. I went through a time 2here I took similar steps. Now I just dont see the results being worth the effort.
It was even hard to read.
You Need To Take Case Hardness Into Consideration (Work Hardening)
This is a good point. I set my die to where I'm averaging in the middle to slightly lower readings on the case gauge. If you set the die too low to where your brass is almost all around the bottom limit, you'll likely see more case separations over the years. Setting your die will drive you nuts because as Ttwwaack pointed out, the different shoulder hardness will give you different final bumps. When I get a decent size die setting, I NEVER mess with it unless absolutely necessary.
This issue drives me nuts on Bolt gun. Because you can feel a few rounds that chamber tight. It lets you know you're not getting a perfect batch of 100% consistent ammo.. even though I anneal 30 cal bolt gun brass. But oh friggin well. You can only go so NUTS doing this stuff.... or you'll never end up doing any actual shooting.
When I reload for my ARs, I use an RCBS case micrometer for 223. I bump the shoulder back to "0" +-.002 (usually it comes out +-.001) when it is processed using a Dillon case sizer/trimmer. I only reload standard commercial or Lake City five times at pressures between NATO and SAMMI. The sixth reload I don't recover the brass - it becomes throw away brass (good luck to the range brass scroungers).
I keep the cases sorted by number of reloads.
In tests I have done the sizing lube has a significant influence on the consistency of shoulder set back. The easiest to use and most consistent I have found is 1:9 lanolin oil to 99% isopropyl alcohol.
I don't use an expander ball since I have found them to stretch properly sized cases. If I want to expand the case neck I use a Sinclair expanding mandrel or if the case mouth needs to be flared (for flat base bullets) I use the Lyman expanding die (intended for lead bullets).
Using this method I have found that the case neck usually splits before any danger of head separation.
High quality brass like Lapua gets a different, special treatment.
Alaska3006
06-04-14, 07:34
I just use RCBS AR small base sizer die......works just fine in my AR.
I keep the cases sorted by number of reloads.
I gave that up. Pappabear can destroy any system of organization.
Using this method I have found that the case neck usually splits before any danger of head separation.
For .223, my brass almost ALWAYS dies of loose primer pocket. I get a 1/10,000 failure for neck split. And maybe 1/30,000 failure from separation.
For .223, my brass almost ALWAYS dies of loose primer pocket. I get a 1/10,000 failure for neck split. And maybe 1/30,000 failure from separation.[/QUOTE]
How do you determine this? Just set that brass aside in a "don't reload again" batch after you decided that's the last time you'll prime that one?
Thus far, if anything seems fishy about a piece of brass after I've cleaned and resized it, I crush that piece with a pair of pliers to ensure it doesn't accidentally end up being loaded up one day. Better safe than sorry, I guess. I'm probably going to learn down the road that I wasted more good brass than I had to...
How do you determine this? Just set that brass aside in a "don't reload again" batch after you decided that's the last time you'll prime that one?
I make the call when I'm hand priming my brass on the coffee table. If a pocket is very loose or the rim is all fux0red up, I set it aside and put two striped on the body all the way around with a sharpie. Then I batch all of the two striped brass, load it, and shoot it together so I can be aware of any popped primers getting into the action.
If the pocket is too loose to hold a primer reliably, I'll kick out the primer and toss the case into the recycle bucket.
The sixth reload I don't recover the brass - it becomes throw away brass (good luck to the range brass scroungers).I scrounge for almost all of my brass, and most of what I've been picking up these days is either PMC or stuff that's still crimped, the latter I know for a fact to be first firing and the former cheap enough I generally assume it's something someone buys to minimize costs ergo they don't reload anyway.
I scrounge for almost all of my brass, and most of what I've been picking up these days is either PMC or stuff that's still crimped, the latter I know for a fact to be first firing and the former cheap enough I generally assume it's something someone buys to minimize costs ergo they don't reload anyway.
This is true. I also NEVER leave brass behind. At usually around 1.85 per pound, it's nice to get some money for the old stuff.
Is it typical to have to toss Federal 223 brass after one or two reloads? I loaded a batch of mixed brass that I have reloaded once previously, and virtually all of the Federal is getting crushed by pliers and thrown in the scrap bucket after I shoot it once more. The PMC, Lake City, and Winchester seem fine after the same amount of reloads.
Is it typical to have to toss Federal 223 brass after one or two reloads?
Yes, that's typical of Federal brass. The primer pockets stretch out preventing the primers from seating very well. From my experience, the primers won't even seat reliably after only one reload... one or two time use brass IMO.
Yep. That brass is weak as hell. If you load a hotter round, it's one load and done.
I've started pitching out brass at decap. If the primer drops out with no effort, it's gone. It's always FC brass or L C 1 0 head stamp. And usually those will have swipes on the head.
Quick brass question-Anyone ever heard of "Frontier" or "PSD" head stamped brass? Is PSD head stamped brass the PMC type that has a smaller internal case volume, or should it be treated like other brass? I'm prepping a lot of 900+ pieces of brass and and all of a sudden I'm finding a lot of the PSD head stamp.
It's too bad the Federal brass is so weak. I seem to get quite a bit of it off the ground at 3 gun shoots.
Breacher 217
07-02-14, 02:55
Tag for future read when I'm not supposed to be sleeping.
Never heard of frontier but psd is pmc they use it in the xtac line. I have never had any problems you might be thinking of pmp. It has a very low capacity
It's too bad the Federal brass is so weak. I seem to get quite a bit of it off the ground at 3 gun shoots.
It's still worth getting a load or two out of it.
I'll still reload it, but once the primer pocket feels loose I think it'll become varmint ammo for the bolt gun for its last load.
Below a Colt Field gauge
http://i122.photobucket.com/albums/o254/bigedp51/headspacegauge006_zps3cdabdf4.jpg
The Colt Field gauge in my adjusted and now calibrated Hornady gauge that reads actual cartridge headspace.
http://i122.photobucket.com/albums/o254/bigedp51/headspacegauge_zps14d3b71f.jpg
Below a fired case from one of my AR15
http://i122.photobucket.com/albums/o254/bigedp51/headspacegauge005_zps20685e73.jpg
Below is the same case after full length resizing and .003 shoulder bump.
http://i122.photobucket.com/albums/o254/bigedp51/headspacegauge004_zps4465b7bc.jpg
After getting the Hornady cartridge case headspace gauge I retired my Wilson case gauges and only use them for paper weights and pen holders.
http://i122.photobucket.com/albums/o254/bigedp51/penholder_zps4213e7d3.jpg
And the resizing bump long and short of it.
http://i122.photobucket.com/albums/o254/bigedp51/shouldersetback_zps59bf1b04.jpg
Yep don't need nor want any stinking guage. Just full length size and be done with it! And My brass gets loaded until it splits at the mouth or will not hold a primer! Which with most brass is 10 plus loadings! Annealing the bras may gets you a few more loading but your primer pocket will get loose first!:rolleyes:
Yep don't need nor want any stinking guage. Just full length size and be done with it!
The gauge was very helpful for me. Both in getting a quick peek as case length, and knowing exactly where to set my sizing die. Just a little bit too high and you're ammo sticks in the chamber.. or worse... won't even go fully into battery.
Too low, and you'll get early separations. The gauge, although not used very often, is a nice thing to have on the bench for any number of reasons.
The gauge was very helpful for me. Both in getting a quick peek as case length, and knowing exactly where to set my sizing die. Just a little bit too high and you're ammo sticks in the chamber.. or worse... won't even go fully into battery.
Too low, and you'll get early separations. The gauge, although not used very often, is a nice thing to have on the bench for any number of reasons.
Amen - From the idiot who bought a new FL Redding die set and loaded 1200 5.56 rounds without the die set down far enough. He found out at the range, when he had to mortar his rifle to get the stuck round out. They were just a bit off, but enough where I can now pull bullets with the best of them.
Amen - From the idiot who bought a new FL Redding die set and loaded 1200 5.56 rounds without the die set down far enough. He found out at the range, when he had to mortar his rifle to get the stuck round out. They were just a bit off, but enough where I can now pull bullets with the best of them.
At least shoot a dozen before loading a pile. Luckily I can test shoot out the back door...24/7.
At least shoot a dozen before loading a pile. Luckily I can test shoot out the back door...24/7.
Yep. I loaded some stickers 5 years back. Taught me to live by the gauge. I kinda pushed it to the upper limit, and my ammo didn't work out at all. I was only 50-100 rounds deep fortunately.
Yep don't need nor want any stinking guage. Just full length size and be done with it! And My brass gets loaded until it splits at the mouth or will not hold a primer! Which with most brass is 10 plus loadings! Annealing the bras may gets you a few more loading but your primer pocket will get loose first!:rolleyes:
http://i122.photobucket.com/albums/o254/bigedp51/badges_zps6e9c9a8f.jpg
GunnutAF You watched one too many old movies with Humphrey Bogart back when they only used the Lyman nut cracker tool to reload.
(and I hope the INS isn't looking for you, and you got your stinkin' green card) :haha:
Yep. I loaded some stickers 5 years back. Taught me to live by the gauge. I kinda pushed it to the upper limit, and my ammo didn't work out at all. I was only 50-100 rounds deep fortunately.
Mark can you recommend a press mounted bullet puller for 9mm Luger. I'd like to have one around, trying to get away from the impact puller. A link to a product would help if you have the time and don't mind, thanks.
Not really. I've always just used the kinetic for pistol. I'd look at sinclair to see if the Hornady cam lock puller is able to pull 9mm. People seem to like that one. I'm running the forster. But for pistol, the Hornady's vertical lever would be much more efficient.
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