Neck Tension Advice Needed

[Husker95]

I'm just getting setup to reload .223 and need some advice on some problems with bullet setback. I have Dillon dies and I am full neck-sizing - the sizing die is touching the shell holder at the top of the stroke. However, when I seat the bullet, it only takes a medium amount of pressure to push the bullet back into the case. I am using 55 grain spitzers without a cannelure and seating to the suggested depth in my Lyman manual (2.260). When I load a dummy round (everything the same but no primer/powder) into my AR it feeds fine but when I extract the bullet has been pulled about .005 further out of the case and my OAL is 2.265. Any ideas? I don't know how I could size it any tighter. In fact, I have even taken the expander ball off of the decapping stem. Thanks guys - I appreciate it. Husker

[BuffCyclist]

If I recall, 2.260 is the MAX OAL for .223, but that's usually because a larger OAL won't fit into mags.

With your rifle may be tighter than others and 2.260" is too long. You might be slamming the bullet into the rifling and then on extraction, the bullet is stuck in the rifling a tiny bit, allowing it to be pulled out.

I would try seating to a shorter OAL and see if that fixes the problem. If I recall, I seat .223 to 2.20" and they work perfectly, especially with 55gr bullets, you'll want to seat them closer to the shorter side of things.

Someone else will chime in either agreeing with what I've said or with something entirely different, if they haven't already done so.

eta: I assume you mean you are full-length sizing (I read full-neck sizing as collet sizing which sizes only the neck). Full length sizing will size the entire length of the brass.

2nd-eta: Check out - http://data.hodgdon.com/cartridge_load.asp
Enter the data for rifle, .223 and compare the OAL for 55gr bullets to 75gr bullets.

55gr are 2.180 to 2.220"
75gr are all 2.250"

[BuffCyclist]

And don't worry, I just did the same thing. When I loaded my first 35 test loads of .223, I loaded them all to 2.260 also, then when I compare them to a factory Federal 55gr FMJ, my reloads were obviously longer, so I looked into it more.

If you think about it, a 55gr bullet is short, and if you have a max OAL length, you will only be gripping the bottom part of the bullet, which is usually tapered and not the max bullet diameter, so it will be looser.

[Great-Kazoo]

Try 2.25 w/out cannelure. With i seat to it.

[ChunkyMonkey]

awww.. I was gonna say, get this...

http://4.bp.blogspot.com/-lABGa3-Hi64/T-RLRMPWSEI/AAAAAAAAABU/RsmkLyAny3Y/s1600/Female_NeckMassage.jpg

[BuffCyclist]

^^ [LOL]

[wilsonpenfam]

I check my neck tension by putting a scale on the bench, getting a hardback book and push down on the bullet till I get to 60lbs. then I measure with calipers to make sure I didn't get any setback.

[JM Ver. 2.0]

I check my neck tension by putting a scale on the bench, getting a hardback book and push down on the bullet till I get to 60lbs. then I measure with calipers to make sure I didn't get any setback.

I hit mine with a hammer.... live primer and all.... live dangerous, my friends.

Sent from my teepee using smoke signals.

[Husker95]

Very funny Chunky - that made my morning.

Wilson, are you doing anything different than I describe to get 60 pounds of tension in your rounds? Are you crimping at all? As i stated earlier, i am FL resizing without the expander ball so about the only variable i have left is my OAL.

Thanks for all the input folks.

[Hoser]

The inside of your sized neck should be about .221-218. More tension that that is bad. Less that that is also bad.

Check and make sure the decap rod isnt bent.

[Husker95]

Thanks Hoser. At work now, but will check those measurements tonight.

[Zombie Steve]

The bullet getting pulled out .003 - .005" is normal if you're using a bullet without a cannelure (can't crimp). Your cartridge is getting shoved forward pretty quickly, and when it comes to an abrupt stop by headspacing on the shoulder, the bullet jumps just like in a bullet puller. Not desirable, but what's a fella to do? Load a little short of max OAL to accommodate for this. If it really bugs you, get a bullet with a cannelure and give it a little crimp.

Generally speaking, everyone gets all wound up about how far they are off the lands. It just isn't going to be a big deal unless you're benchrest shooting. The old rule of thumb is that you want to have one caliber length touching the neck (in this case, .224") minimum. With a flat base bullet, that's easy. The boat-tail part of a boat-tail bullet obviously isn't touching, and neck tension can be an issue. Seating a little deeper usually helps. If you can get contact with the whole neck, so much the better.

Some other things to check - what do your bullets measure? .224"? Not unheard of that they'd be undersized and got through QC, particularly as manufacturers are running full steam 24/7. Also, as Hoser said, measure the inside of the case mouth after sizing and see if it's a die problem.

Hope this helped. Good luck.

[Husker95]

Thanks for all the info guys - i appreciate it. With Hoser's data in mind, i looked at my newly sized cases and followoing FL sizing, i have an inside neck diameter of about .219. That gives me a lot of reassurance that my dies are good and the cases are sized correctly. I worked up a dummy round with a 55 gr spitzer seated to 2.25 and it chambers and extracts from my Armalite just fine with only a small amount (.004) of bullet withdraw from the case when I extract. The only thing that concerns me a little is that i still can push the bullet into the case if i push pretty hard on it with my hand. I'm still not sure why that is - but i did work up a test batch and will test fire this weekend and see how they work.

[Jamnanc]

Is there a reason your not using the expander ball? Have you read the instructions for the seater die carefully? Lee seaters have a taper crimp built in. I set mine so I can just barely see that the die has touched the case mouth. It's possible your actually over crimping and the brass bounces back to size while the bullet doesn't. This causes looseness. Try backing out the die body a turn and resetting the seater itself. This may help.

Eta Dillon two die sets have the taper built in too.

[BuffCyclist]

So, you chamber a 2.250" dummy round and on extraction it measures 2.254". Your first post indicated it was pulled out 0.005", now its 0.004".

Just out of curiosity, I grabbed my AR (S&W M&P15T) and dropped in a dummy round, from a magazine and extracted it. Here are the measurements: Before Chamber - 2.221". After Extraction - 2.225". Did it again with the same round and after 2nd Extraction - 2.227".

I would guess that this is normal and must be due to the chamber/extraction process. Mine are even crimped with the Lee Factory Crimp Die. I don't think it matters as you will hardly ever be extracting live rounds...

eta: Just tested this with some factory Federal bulk ammo.
Before - 2.190"
After - 2.192"

[Rabid]

From Sierra

Neck Tension

When we stop to consider the vigorous (read, downright violent) chambering cycle a loaded round endures in a Service Rifle, it becomes pretty clear it suffers abuse that would never happen in a bolt-action. This is simply the nature of the beast. It needs to be dealt with since there is no way around it.

There are two distinctly different forces that need to be considered: those that force the bullet deeper into the case, and those that pull it out of the case. When the round is stripped from the magazine and launched up the feed ramp, any resistance encountered by the bullet risks having it set back deeper into the case. Due to the abrupt stop the cartridge makes when the shoulder slams to a halt against the chamber, inertia dictates that the bullet will continue to move forward. This is exactly the same principle a kinetic bullet puller operates on, and it works within a chamber as well. Some years ago, we decided to examine this phenomenon more closely. During tests here at Sierra’s range, we chambered a variety of factory Match ammunition in an AR-15 rifle. This ammunition was from one of the most popular brands in use today, loaded with Sierra’s 69 grain MatchKing bullet. To conduct the test, we chambered individual rounds by inserting them into the magazines and manually releasing the bolt. We then repeated the tests by loading two rounds into the magazine, chambering and firing the first, and then extracting and measuring the second round. This eliminated any potential variation caused by the difference between a bolt that had been released from an open position (first round in the magazine) and those subsequent rounds that were chambered by the normal semi-automatic operation of the rifle. Measuring the rounds before chambering and then re-measuring after they were carefully extracted resulted in an average increase of three thousandths (0.003") of forward bullet movement. Some individual rounds showed up to seven thousandths (0.007") movement. Please bear in mind that these results were with factory ammunition, normally having a higher bullet pull than handloaded ammunition.

To counteract this tendency, the semi-auto shooter is left with basically two options: applying a crimp or increasing neck tension.

[Husker95]

Is there a reason your not using the expander ball? Have you read the instructions for the seater die carefully? Lee seaters have a taper crimp built in. I set mine so I can just barely see that the die has touched the case mouth. It's possible your actually over crimping and the brass bounces back to size while the bullet doesn't. This causes looseness. Try backing out the die body a turn and resetting the seater itself. This may help.

Eta Dillon two die sets have the taper built in too.
I took the expander ball off because I thought it was overexpanding the neck causing my issues with bullet looseness. I am using a Dillon 3-die rifle set.

[Great-Kazoo]

So, you chamber a 2.250" dummy round and on extraction it measures 2.254". Your first post indicated it was pulled out 0.005", now its 0.004".

Just out of curiosity, I grabbed my AR (S&W M&P15T) and dropped in a dummy round, from a magazine and extracted it. Here are the measurements: Before Chamber - 2.221". After Extraction - 2.225". Did it again with the same round and after 2nd Extraction - 2.227".

I would guess that this is normal and must be due to the chamber/extraction process. Mine are even crimped with the Lee Factory Crimp Die. I don't think it matters as you will hardly ever be extracting live rounds...

eta: Just tested this with some factory Federal bulk ammo.
Before - 2.190"
After - 2.192"

Some of that OAL increase is due to bolt carrier slamming in to battery.

[BuffCyclist]

Some of that OAL increase is due to bolt carrier slamming in to battery.

Exactly (that's partly what I meant by stating its due to the chamber/extraction process but probably should have stated explicitly), which is probably what the OP is experiencing too. That's also mentioned in the snippet Rabid posted.

[stubbicatt]

While difficult to gage, time wise, if you are having issues where the bullet is either pulled out by the rifling or jumping due to chambering forces, you can first really brush out your case necks with a bronze brush so bare fresh metal is exposed, load your cartridges, and let your handloads set for about 6 weeks. They will often "cold weld" and you may remedy your situation.