Jump to content

Neck tension


No i deer

Recommended Posts

Redding s type bushing die.

My measurements add up to how i turned them.

As I had some brass that was from the previous barrel I matched the new brass too it.it chambers and shoots great before anyone says no no no start with fresh brass.

Old barrel was a 313 neck chamber.

Brass was turned 13 thousanths clearance in the chamber with a 308 bushing.

My new barrel Is a .314 chamber so turned the brass to .0135 rather than 14 thousanths for 2 reasons.less neck tension and just incase the cases got mixed up which they haven't.ive not changed from the 308 bushing thinking I had 3 thousandths neck tension max

 

Over all measure add up with bullet seated but measuring inside the neck of a sized case is

.280 being 4 thousanths tension.

Do I get a 309 bushing and see if it does actually reduce it to 3 or used the 310 i have in my 284 die which should give 2 to 1.5 thousandths tension and switch it back and forth.at least that way it gets cleaned regular ?.

I've entered the European individual  f class open championships 

And need to take my best game.ive got a very accurate load and found Saturday my ES was several fps too much.this fraction less neck tension should hopefully be the key.

 

Link to comment
Share on other sites

Yes it looks and sounds very clever but is it another gimic......?

Show us some evidence ?

I see no realtime advantage over the s type bushing dies until proven wrong...!

It's nice seeing you marker being placed exactly where you've aimed it  at 1000yds ?.

Spud has a 309 bush in stock ?

Tonite I will try my .310 bushing first and see what the inside neck measure is and seat a few bullets to get a feel of the seating and see if they're held firmly enough that I can't pull them out with my fingers.

Monty are you shooting the individuls at the Euros ....?

I will be using my 7mm saum 

Link to comment
Share on other sites

13 hours ago, No i deer said:

Is there a minimum neck tension that the bullet needs too work....?

It's for a range cartridge and the bullet will be jumping to the lands.

No, so long as the neck holds the bullet with sufficient tension to maintain the same CBTO measurement then it will work but the term work is very loose indeed and really means nothing.

Will your rifle be consistently accurate with 0.0005" compared to say 0.005" of neck tension or vice versa? 

Is a specific neck tension more relevant if your jamming rather than jumping the bullets?

Does the powder you are using work better with more or less neck tension?

Will differing neck tension make any real difference to most people?

There are answers for all of these questions but only you and your target will find out what works for you if your looking for the highest levels of accuracy you can get. Mostly 0.002"-0.003" of neck tension will work fine for most people most of the time in most situations. How deep you then explore this area and the level of understanding you end up with is then down to how committed you are to finding the answers and how solid your testing/verification process is.

Link to comment
Share on other sites

Thanks Al.

I will try my 310 bushing tonite .Check.the measurements and test some more ammo purely to see if less tension has reduced the Es.

If it has then I will see if it has affected it's accuracy

Powder wise it's within 1 kernal or as accurate as the gempro 250 is...

Link to comment
Share on other sites

The .310 bushing gets me and inside neck measure of .282 so I will try it out with the same load.3 of my 4 shots tested over the chronograph Saturday was within 7fps but I had one drop off of 10fps stretching it to 17fps.

 

Link to comment
Share on other sites

I went out this evening to chrony some loads and it started raining.must of waited an hour for it to ease but it kept spotting and causing error from the rain drops landing on the photo cells.i was rushing back n forth try to wipe the cells off and quickly fire.i had some good Es's with a really odd figure which said to me rain or I may have aimed a little higher over the photo cells and light was fading too.

I had another go before I gave up getting 2fps ES from 3 shots out of 4 then again the stupid figure that I don't believe is true.i didn't get to fire a 5th shot because of the rain.i will resume testing tomorrow.

What I did notice from the 9 shots I got off from 2 batches is I got an extra 10fps from a 2 thousanths neck tension than I did from a 1 thousanth neck tension.

3 shots out of the first batch was 7fps  ES on 1 thousanths neck tension on CCI Br2 primers.

The second batch was CCI BR2's on 2 thousanths neck tension.

The remainder to test are with muroms 

 

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use and Privacy Policy