Neck Clearance and Neck Tension: ctdshooting
ฝัง
- เผยแพร่เมื่อ 25 ก.พ. 2023
- Jason Stanley with www.ctdshooting.com/ starts with the basics of neck clearance and neck tension then quickly moves to the advanced level. The handloader can then pick the information that best suits their level of precision. For a written version go to: www.ctdshooting.com/post/neck...
Want to learn more tips like this? Subscribe: www.youtube.com/@ctdshooting/... - กีฬา
I've watched a zillion reloading videos over the last few years, and this is the first time I've ever heard the term "neck clearance". It's always good to learn something new.
We are all students. I'm glad you got something out of the video. Good shooting.
What a great topic. Great job explaining neck clearance. I will be using your calculations a lot going forward. Thanks!
Glad it helped. This is a great example of what CTD is all about. You already have a process that has been working, now you can take one item to make your process better. Thanks for the comment.
My approach is simple: Anneal after every firing, full length size with a standard sizing die with expander ball removed. Set neck tension with a mandrel 0.002” under bullet diameter.
I feel like setting the ID of the case mouth via bushing die is more complicated than via expander mandrel.
Cheers
Thank you for taking the time to comment. The method you use sounds like it has some advantages.
Winning in the wind is another good channel. The math on the white board is very helpful. Thanks,subbed.
Yes, lots of good information on that channel. Hope you were able to gain or two ideas.
@@ctdshooting yes I did as well looked at some of your other titles, I will be back to view as this topic is something I have been working on. I need better groups at 300 yds so these points make a difference
Thanks for the detailed explanation and the link to the written version. The written version will be a helpful reference at the reloading bench. The is the first time I have heard the term Over-Bullet-Measurement (OBM), but it will now be part of my reloading vocabulary.
Thanks for the comment. I'm glad you found the information useful. I have no idea who coined OBM but it is a lot easier than saying "measure over the case neck where the pressure ring sits" Plus, not all bullets have pressure rings. Thanks again
Thank you. .002 just what I see on SAMMI prints.
Great video!
Thank you
Most excellent, thanks for this info and excellent definitions.
Absolutely. I hope you are able to add one or two items to your current process.
Great video
Thank you. I hope you were able to take one or two items and apply to your current system.
Great video! I bought pin gauges to measure the inside neck diameter or neck tension. Saves me some math. Neck clearance is super important. Having too little neck clearance and a carbon ring will have you chasing your tail wondering why the load you developed is 100 FPS faster than it was.
Excellent comment.
Good info. Thanks!
Thank you. Hope you were able to add to your current procedures.
great info thanks for sharing
You're welcome
May be a dumb question but I'm learning into my second year. How do I measure my neck clearance or diameter to achieve my 2 thousands I hear this alot. Also carbon on the neck is from the neck not trapping gas or in time. Thank you for your reply or any comments welcome.
Absolutely not a dumb question. Neck clearance is the OBM (covered in this video and in depth in this one: th-cam.com/video/xs4h_zscjVc/w-d-xo.html) subtracted from the neck chamber dimension. For any of my custom barrels, the gunsmith tells me what the chamber dimension is. For my over-the-counter hunting barrels you can use a chamber cast or you can use the SAMMI specs. Personally, for hunting barrels, I use the quick check method for neck clearance (roughly 3:10 in this video) For hunting barrels I feel that is good enough because there are much bigger pieces to the precision puzzle. Now, neck tension....that's a different story and much easier to control. Hope this helps
Good video!
Thank you
Use cerrosafe casting alloy. Brownells.
I'll give that a try on my new rifle. Thanks
Thank you for a really informative video. I have always thought that neck clearance difference, real versus theoretical, was due to spring back.
Thanks for the comment and question. Spring back probably plays a role in neck clearance, but more importantly it definitely plays a role in neck tension. Spring back is related to work hardening. To stay at the "knife's edge" of precision, one has to control work hardening of the brass. Having the proper neck clearance helps with that. As always, this is dependent on the level of precision you are after. Hope this helps.
Mr. Seely. I might not have answered your question last night. My apologies. I have found the biggest differences in theoretical vs actual was due to my measuring (I am not a machinist and I am trying to measure to .0001 = any little difference can change my overall answer and/or any "mistakes" when I turned the necks. This is not to say that spring back does not play a role, just my own human error probably has a bigger influence on measuring the clearance. Now...neck tension...that might be a different story.
Jason, you did fine last night with your answer. I was just trying to wrap my head around aspects that I haven't considered. But all these things do play an important role, I believe. All of my rifles except my heavy benchrest Nosler 28 rifle have SAAMI necks. The Nosler has a neck size from my custom reamer and factory cartridges won't fit in the gun. I have to turn necks down to approx .009in or the round will overpressure. So these aspects are important to me. Thanks!, Jeff
@@Jeff_Seely I've heard lots of good things about the 28 Nosler. One of the hard things about discussing techniques and tips is matching the information to use of the rifle. I wrote a blog on that called Precision Ladder www.ctdshooting.com/post/precision-ladder Sounds (reads?) like you have a pretty good grasp of things. Hopefully my videos/blogs can simply add a few items to your current process. Have a good one.
Yes sir. I can imagine that it is and will look thru your blogs. Your YT channel here is informative and relevant. I have enjoyed watching it and look forward to new videos as they come. Thanks for the time, effort, and expense in producing them!
Thank you and God bless to all
You're welcome. Hope the video gave you something to add to your current process.
Great video thank you! I just acquired a 30BR. Im rolling around in my head about what you said about bushings not sizing to what they are labeled. I have been under the impression that the different results are due to brass spring back. Not every piece of brass acts exactly the same. So now i need to go test all my bushings to see if im getting results like you. Very interesting, thanks again! Always trying to add info to my mental tool box
Absolutely - work hardening can affect spring back, which is why many anneal their brass. However, there are manufacturing tolerances also. For example, I am tuning a 6 mm AI and would like to have .003 neck tension. I bought a .271 bushing and it resized the "freshly annealed" brass to .2704. So...I bought another .271 bushing from the same company and it resized the same brass to .2719. It is the nature of the beast. Thanks for the comment.
@@ctdshooting thanks for your reply. I do anneal also. Started competing with 6BRA and ramping up for 30BR and 6PPC. Trying to absorb as much info as I can
Very interesting 👌
Thank you
Excellent video. I've heard Eric cortina and f class John bring it up but not go in depth.
Thank you for the positive feedback. Mr. Cortina has some super good videos. I'm not familiar with F Class John, but if you mentioned them two together he must be pretty good. Hope the information in the video helps in some way. Thanks again
Is it necessary to use a mandrel? I wish you would discus the mandrel business as well. Thanks
Thank you for the question. I am assuming you are asking about the resizing mandrel (many times called the button or expander ball) and not a turning mandrel. I only use bushing dies. When a decapping rod has the button on it, I take it off before using.
However, the measurements would still follow the same process because resizing is completed (which ever way it is performed) before you measure the resized portion of the neck. I have never tried to buy different buttons to adjust the neck tension, so I can not comment on that. I will add this to my "to do" list of videos. Thank you for the question and suggestion. Stanley
How would I find my neck chamber in a store bought rifle? Or is there a standard?
You have a couple options. 1 is to look up your cartridge in saami.org/technical-information/cartridge-chamber-drawings/. This should get you decently close then use the quick check methods described in the video around the 3:10 mark.
2. Perform a chamber cast. 3. Use pin gauges (if they are long enough to reach the neck area of the chamber, you may have to take the barrel off if they are not) 4. Gunsmiths may know other methods.
Personally, I really pay attention to this number on my level 3 and level 4 rifles. Level 1 and 2 I just make sure I have enough and get the rifle shooting good. Hope this helps.
Ive noticed that on my 220 Russian brass after its been neck turned and fired 4 to 5 times. I M getting a donut on the inside of the neck. I can drop a bullet in it but has resistance... would you suggest a inside neck reamer?
Has this neck been expanded? (for example to 6 mm) Generally inside donuts form below where the bullet is seated and really don't affect anything. If your rifle is shooting the way you want, I would leave them alone.
If the donut is interfering with the seating depth or neck tension then yes you can purchase an inside reamer to take them out. You will have to measure very precisely as to only get the donut - not the neck walls. Caution - You might want to remeasure for tension and clearance after you do this - just in case you took off more than just the donut. Hope this helps.
@ctdshooting yes been expanded. Yes the donut it right at the flat base line of my bullet. I just noticed when I placed a bullet base down in the case. I had a lil resistance but I don't think it's interfering with seating depth
You're probably good to go and if the rifle is shooting good - then I would no mess with it. In my experience the donut (both outside and inside) were formed during expansion. When you outside neck turn you take the outside donut off. When I make the 30 BR brass I get the same thing. I have different inside neck reamers to just barely skim the inside of the neck which removes this inside donut. However, many great shooters (some Hall of Famers) don't mess with the inside donut. Hope this helps.@@redraiderreloading7612
What happened to fire forming the case or am I just old school ?
Fireforming is (in my opinion) important. Here is the video/Blog I wrote on the subject www.ctdshooting.com/post/fireforming-you-only-get-one-chance-to-make-good-brass
Nothing wrong with "old school" but I'm not sure I understand your question in regards to neck clearance/tension.
😊
👍🏼
You don't use a expander mandrel die? I would like to know why pls
Thanks for the question. I use an expander when I make 30 BR cases for competition (6BR expanded to 30 BR). I then use custom pilots on my turner to match up with the ID of the case. When I turn or clean up the necks on some of my other rifles I use pilots and no expander. I hope that answered your question. Thanks
@@ctdshooting awesome 👍🏽
use mandrels THE END !
I'm glad you have something that works for you.
@@ctdshooting I will admit I like that chart you use ; very easy to understand range for neck tension.
Great video
Much appreciate the kind words. Glad you were able to find something useful.