Accuracy tips for 300 Blackout brass...Lee collet die and shoulder set back... 

Thanks as always for keeping the channel on your radar!

Thanks for the nice comment. I hope, if you try this you get great results. Come back and let us know what you find.

Hey thats great! As for neck sizing only in an AR, (for me) I wouldnt be comfortable with NO sizing. You really want the bolt to be able to rotate behind the lugs fully so the bolt teeth are 100% supported. I am not saying they arn't but I would want to make sure. In a bolt gun you can cam the bolt handle and see its closed, an AR is a little more difficult. Nothing stopping us from a minor set back and still using the collet die. Note, if you are talking about the 300 Blackout, the shoulder is so slight it probably would go into battery anyway. Thanks for watching.

I have really become a big fan of the collet dies over time. They have a much broader value than they are marketed for. I have been lobbying Lee to make one for the 6.5 Grendel for a while now but they change course about as fast as the continents drift.

This collet die really works. Lee is stuck thinking it is just for neck sizing if your not full length sizing but you can do both and get results. It is the best treatment for a concentric neck I am aware of. Everyone goes on and on about the "bushing dies" nothing wrong with them but mostly they take the problems on the outside of the neck and move it to the inside of the neck. The collet die irons out the neck from both sides. If you have a cam over press, be very careful, it is really easy at the bottom of the stroke to get way to much force. You will strip the retaining nut in a flash. As much as I preach this, I just did this to one of my own dies. Im a part time idiot lol.

@@TreeTopFlier Thanks for the tip! I have a Hornady classic press that cams over so I'll have to be careful...I'm about to try out some leatherhead 220 grain cast projectiles but not sure if they will fly straight for me due to my 1/8 barrel or if it will lead it. Have any success with reasonably priced sub projectiles that you can recommend?

The collet die is a great way to improve brass consistency.

Hello, and thanks for the comment. I do usually lube the inside of the necks during resizing every few cases. This is not a very deliberate thing though, I usually just scrape my finger over the rim of the case to get a little inside. If your pin is not holding fast in the split nut, pull the pin and throw some calipers on the stem where the nut sits and see if it is the same size as the rest of the stem. Seems like Lee may have had some expander pins go through that were too soft and the pin got swaged down during tightening. Once this happens you cant get enough clamp to secure the pin. They are a warrantee item. As for the collet die, yes I use it a lot. My current process (subject to change), as part of brass prep, is to resize the brass so I can trim to desired length, cut primer crimp etc. Later, when I decide to reload especially on a turret press, I put the collet die in the first position, where the sizing die would have been, and complete the normal cycle. About the collet die. Many high end reloaders use a mandrel to do a better job of expanding the neck than the expander ball does. The collet die is basically a mandrel ++, since it can clamp the brass neck around the mandrel in a swaging motion. Since neck tension is a huge part of accuracy via ES and SD numbers, I feel this makes a difference across the board. When you use it, you can feel how easy it goes into some cases and how hard it is to get into others indicating quite a variance from case to case. Even this has its limitations as brass tends to spring back. Next best is to do this on annealed brass. Best is using super expensive purpose made brass (Lapua). I think Lee is missing the mark a little by just advertising this die as a neck only sizing die instead of a deluxe mandrel die. Sorry for the long reply but this is an interesting topic.

So do you use this process on all calibers or just select calibers. I’m shooting & reloading 223, 300 BO, and plan to start 308 win and 30.06. Interesting that you note annealing. Building a gas annealer for 223 and larger but was toying with using an induction system for 300 BO since the cases are so short. Curious of your thoughts on annealing 300 BO

If I have a collet die for a cartridge I add that step. It doesnt do anything if everything is correct but if the neck is a little tight or the mouth is belled etc. It will fix all that up. I dont have an annealer so if I do it I do it old school with a drill and a torch. I have good luck with larger thicker cartridges but have had some frustrating results with smaller thinner cartridges like 300 blk. My methods are crude lol. I find a cartridge that has runnout after sizing. Then I chuck it up and spin it in a flame. When the flame around the case starts to turn orange I count to 4 and pull it. Once cooled Ill run it through the sizer and if it is soft enough to straiten out and fix the runnout, I make a note of the count and do all of them at this count. Some times I have to add a second or two for the brass to give up its bad memories LOL.

Yes, the collet die mandrel will uniform the inside diameter of the neck. You can order custom mandrel diameters also. When you run sized cases into the collet die you can feel the difference from case to case as it pushes through the neck. Some will take more force than others. It's a great tool.

I cant visualize this? I replied to your other post.

@@TreeTopFlier place case in ram shell holder...lower washer over case to sit on shell holder. If unclear..I'll post a video...

@@TreeTopFlier ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE--_pfn5h4i34.html

ok, now i see, but im still at a loss to understand why this is necessary. Best i can come up with is still too much force for the die. And possibly the brass needs to be annealed. Maybe give that die another turn?

Interesting that the subs have less shoulder lengthening? Ive never noticed or maybe never looked. I dont shoot much subsonic. There really is a lot of set back with a full length die. The collet die makes a difference with accuracy in all my testing better for standardizing neck tension. My process is to form or resize, shoulder set back .003-4" check length and trim then chamfer. When Im ready to reload, I use the collet die in the first position on my turret press and carry on loading from there. Sometimes I will pull the expander ball on the FL sizing die and just use the collet die as a mandrel. Marked under, things to try. 300blk is an interesting versatile cartridge. The chamber specs are set to a more military type standard since that was the project (looser for reliability). Accuracy can be a challenge. The freebore is long for big subs and a little wider than necessary for civilian application. This gives the projectile a chance to get squirrely before making it to the lands. Hoop dimensions dont really effect pressure so some manufactures may tighten those dimensions resulting in better accuracy. Think 223 wylde like dimensions. Ive seen some shoot really accurate, sub MOA and others 1.5"-2.0' Thanks for watching and commenting.

I saw your reply in email but not on here??? Anyway, that sounds odd to have so much head space. At second look, that does look long to the shoulder. I have one that measures 1.075 and one that measures 1.083" so .005" shorter than yours. I guess if you only have one barrel your loading for and you dont mind setting up for a custom headspace when resizing it wouldnt make much difference. May even give you a little more case capacity and lower pressure threshhold. Drop us a note with what they say.

I've been talking with JP Enterprises on my concern and I'm waiting to here back. I deleted my original post in case I found that I was thinking about this all wrong. When using the hornady comparator, the headspace gauges I have measure .0065" shorter than what they are labeled. So I've been adding the 0.0065" to the measurements I've been taking on my brass as I think that is more accurate and correcting for using the hornady comparator. So brass has been measuring 1.082" but after adding the 0.0065", it ends up being around 1.088". The 300aac chamber spec for headspacing is 1.079"-1.089" so my concern is that the chamber is almost out of spec and within a little more use, it will be out of spec. JP is looking into it though and I think they will end up having me send in my barrel for inspection.

Sounds like your not using a digital caliper that you can zero on the comparator. They are called comparators for a reason, they are really only relevant from one case to another measured with the same setup. The headspace no go fail is kind of a big deal though.

Ended up borrowing a few of my buddies new 300aac guns and they all take my no-go gauge as well. All these guns have low round counts on them and barely take the no-go gauge just like my gun. Fired brass from their guns measure around 1.081"-1.082" which seems normal from what I've seen on different forums. I do have digital calipers and I have been zeroing on the comparator as you advised. As you mentioned though, I should not have been adding that 0.0065" to my measurements. I was only doing this because my headspace gauge was measuring that much less than what was engraved in the gauge. So I believe the headspacing is fine but I think that the headspace gauge I have is out of spec. I'm going to get some new headspace gauges and try them out. I am interested to see what these new gauges will measure using the comparator.

The Redding press is a cam over press with insane amount of force possible at the bottom of the stroke (probably the most leverage of any). I bet you can crush a penny at the bottom of the stroke if placed between a shell holder and bottom of a sizing die (I can on my RCBS). You definitely want to choke up a bit on the stroke to use a Lee Collet die with that press. They usually blow the end cap out. The mandrel should be .002" undersized to the bullet. So a .308" would measure .3055"-.306. Lee has the end caps and fresh mandrels on their website. You will probably need to get a new mandrel if it has been swaged by force. You cant really feel the sizing action but you can measure the results. I try to use the same force on each case. For the drag on the mandrel, If you closed hard on your empty die, you can deform the pedals of the collet. Lee says to disassemble the die and pry the pedals of the collet back apart a little so the gaps are equal from the base to the cone. Also, use a little lube on the inside of the case mouth and for bonus points, it never hurts to chuck mandrels and expander pins up in a drill and spin them in some 000 steel wool to really smooth them out. Before you order parts, I would also inspect the collet cone and seat for damage. In extreme cases you can damage those mating surfaces too. I've done all of this with my experimentation LOL. Learning curve Call Lee, they will take care of you, they always have me. Setting a seating die on your press: Lower to the bottom of the stroke. For Lee: Screw the die in until it touches. If its a carbide ringed die for hand gun, stop there and tighten the lock ring (camming over on a carbide die will crack the carbide!). If its a dead length seating die, drop the ram, and tighten 1/4 more, re-raise the ram and tighten the lock nut. On either, after the body is set, adjust the bullet seater to desired length. If its another brand you set the body of the die to use the included crimp or not (generally) Hope this is helpful

@@TreeTopFlier I polished the mandrel...with wet n dry 1200...briefly...that's when I discovered the deformation by feel. Have ordered 2 more mandrels...I like to one without a decapping pin so, if, a primed cartridge won't seat a bullet, I can resize, without depriming. I did manage to damage the cone part of mandrel when removing the mandrel from it when it was held on by the separated seized neck. This also happened on my Lee press... But I carefully removed burrs. .and.. .used some chrome polish, turning the collet in the mandrel by hand. I'm pondering doing this to my other dies .. Using the washer over the case seems to have stopped my problems...with 17rem.. with other calibre collet dies I don't have this problem. I miss the "feel" of the Lee press and collet die. That was pleasant. The big boss is a bit "ghostly" on the collet.. sometimes a mild feel of collet closing...I try to hold consistent pressure too..but...there's no feeling. If only Lee made special case holders for collet die..in order to reduce amount of neck being sized...fiddling with the washer everything is no fun.. With the seating die, Lee, I might just give it half of a quarter turn for mild cam over...idea being less wear on press, but still positive cam..I'm not sure how camming the press effects wear and tear on the press...might make no difference at all. Thanks for response...it's been a learning experience...after...years of reloading...

It is a little hard to get consistent pressure...its a feel thing. Some guys have experimented with making torque wrench handles for their presses. Just another variable to control. The context of this video is using the die with a full length sizer in the AR platform. In the bolt rifle the collet die is a nice option without full length sizing door.

I think for your application it probably does more good than trying to neck size only for bolt gun, that didn't work for me.

If the neck wall thickness is too much then collet die cant fix that. Turning is the best bet. BUT, before I went down that road I would try them in the chamber I plan to shoot in. Chamber gauges are nice but they ensure everything is sized to the absolute minimum chamber dimension so they fit in every possible gun. Most likely your chamber is some where in the middle. I'm assuming this is a loaded cartridge problem showing up because the neck is too thick. Up to .013" is usually ok then you start running into problems. This is usually associated with converted cases. Not all head stamps are suitable. If you want to throw some numbers at me I would be happy to help troubleshoot.

@@TreeTopFlier I downloaded the list of brass good and bad and I find that pretty spot on, My chamber neck is right at .337"- .338" (measured off a shot case) and it seems neck walls over .011"-.12" can be a bit sticky. What I'm learning is when I form Norma brass with the mandrel it really tugs removing the cases from the press. So I'm forming the outside neck going in and then opening the neck back out on the way out if the wall thickness is too thick. When I don't use the mandrel outside cases fit perfect however when I seat a bullet, they don't fit. So I either sort all my range brass to go and no-go piles or I add a neck trimming step. With the 300 BO I will sort the brass and use the thick wall cases just for 223 reloads. Now the hard part... 8.6 Blackout, these have same exact problem I'm reforming 308 cases, specifically Lake city Brass from 2004 thru 2021 head stamps. All have thick necks, so it's neck trimming city for me.. However when I convert 6.5 CM Hornady or Winchester, no neck turning. But my 6.5CM I use for 6.5CM. But I just bought 250 rounds of the LC so I need to use it. Would you believe it has the same mandrel issue as the 300BO, makes sense same thick walls... So when they are hard pulling out of the forming die with the mandrel I instantly know, thick wall case. I do see these lake City neck walls .013"- .017" and they vary. The Hornady brass after seating is a consistent .365 but the lake city is .368-.370" Now Faxon advises their barrels have a chamber neck of .370" but a measure round with a .370" neck wont chamber in the 16" Big Gunner nothing over .367" even thinks about it. I sure hope a case gauge comes out soon as its a pain using my AR10 upper to check if the rounds fit. Now I reading that there is a suppressor called Rugged Alaskan 360 that can handle everything from 223 thru 338 Lapua including 9mm! One Can to Rule them all, sounds promising. But need to get this sorted first.

Hey Scott. Just to make sure... the Lee Collet die is a neck only sizer it uses the mandrel to set the inside diameter of the neck for the bullet. When the shell holder touches the bottom of the collet die it closes around the brass neck on the mandrel. The constant is the mandrel diameter. Regardless of the neck wall thickness, the neck tension should be roughly the same, minus irregularities in brass spring-back and case hardening. If your talking about a full length sizing die, and removing or installing the neck expander pin, then yes you would be way to tight for a bullet if you sized without the expander ball. I sometimes do this and then use a collet die to expand the neck with a little more precision but somehow you need to open the neck back up to set the bullet. Looking at the numbers you provided, you shouldnt have a problem in your chamber. If your fired cartridge has a neck dia of .337. The numbers are like this, lets say you have a neck wall of .013" after seating the bullet the neck will accommodate it. Right side neck, .013"+ .308"(bullet dia)+.013" (left side neck)= .334" Which is still .002" under the saami max for this ammo. And yes, on a regular full length seating die, pulling the expander ball back through the neck when the neck wall is thicker on the brass will take more force. A little sizing lube on the inside of the neck will make it less noticeable. Case gages are a nice tool to find big problems but not every rejection is a real for every firearm once you know why its failing the gage then you can move on. All this applies to 6.8 blackout too just with a different set of numbers. That suppresser sounds nice, Im a swiss army knife kinda guy. One and done. Hope something in here helps. Check out my neck turning video.

Come to find out inside the neck reaming is ONLY to be done on fired brass. Never done on formed brass, formed brass like brand new converted 300 BO or 8.6BO these require a custom ground reamer size from Forster. The good thing is the only a charge of $20 over the cost of the reamer for a custom size, I was told send them some brass I formed and they will grind the reamers to match! Boo Yah! A solution! I hope…

Interesting. Reading it, I wonder the advantage of neck reaming vs neck turning? Seems like turning would be easier and adjustable to control neck wall thickness.

How ever you true the neck it will have an accuracy effect. As i continue to learn, i have really come to realize how vital the brass case is to accuracy. I think of it as the womb of an accurate shot.

Sorry I am so late getting back with you. I didnt see this comment. I use the collet dies very last. In other applications I size and trim my brass so its ready to reload and when I get on the turret press, my first station is the collet die. instead of a traditional sizing die.

@@TreeTopFlier Thank u