Case Neck Concentricity

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   Well researched!
In an era of going by "feelings" its refreshing.
It almost exactly duplicates my results from years back, when I go into an "accuracy craze".
I think I posted the saga on here?
That was when I stopped all the absolute custom loading & just started making good loads that shot well.
My "Standard" loads, beat my "Custom Loads" by a respectable margin

I still do the "Once & done" steps, like flash hole reaming & primer pocket uniforming, & to me, "Partial Full Length resizing" but don't do the extreme steps. This may well not apply to the smaller & IMO more finicky 5.56/.223 reloading though.

Partial F/L resizing used to be a standard thing to match hand loads to individual guns. IMO it was a skill that should not have been relegated to the "extreme accuracy nutters" segment of reloaders.

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Shamu Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Logo Designer / Donating Member Joined: April 25 2007 Location: MD, USA. Status: Offline Points: 20510	Post Options Post Reply Quote Shamu Report Post Thanks(0) Quote Reply Posted: June 23 2023 at 3:41pm
	Well researched! In an era of going by "feelings" its refreshing. It almost exactly duplicates my results from years back, when I go into an "accuracy craze". I think I posted the saga on here? That was when I stopped all the absolute custom loading & just started making good loads that shot well. My "Standard" loads, beat my "Custom Loads" by a respectable margin I still do the "Once & done" steps, like flash hole reaming & primer pocket uniforming, & to me, "Partial Full Length resizing" but don't do the extreme steps. This may well not apply to the smaller & IMO more finicky 5.56/.223 reloading though. Partial F/L resizing used to be a standard thing to match hand loads to individual guns. IMO it was a skill that should not have been relegated to the "extreme accuracy nutters" segment of reloaders.
	Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)

britrifles Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: February 03 2018 Location: Georgia, USA Status: Offline Points: 8404	Post Options Post Reply Quote britrifles Report Post Thanks(0) Quote Reply Posted: June 23 2023 at 3:55pm
	Shamu, I suspect I’m just “reinventing the wheel” here, because it’s hard to find any factual evidence. No doubt in my mind that bullet runout is a big deal with some bullet types and some barrels. I struggled to get good 600 yard scores with my AR and I’ve finally resolved that issue, it was because of poor bullet runout. But, it seems to be a negligible variable in the No. 4 with the 174 SMK. Now, that could be because I’m shootings these loads in a barrel that has a lot of rounds thru it and the throat has been blasted away. On a new barrel, it may be a different outcome. I need to accept reality that this old shot out BSA 5 groove has served me well and it’s time to replace it. The days of 10 consecutive shots in the X ring are now gone. Today, my ten shot groups fired prone were 2.4 MOA and larger. Just a year ago, it was still shooting under 2 MOA with a high X ring count. I have a new Criterion and a new Lothar Walther barrel to choose from, so time to get on with the job before the next major match. In a scoped high precision rifle shot off the bench or bipod, I’d expect bullet runout to be important, but not with our Lee Enfield service rifles shooting in position with iron sights. Im convinced…

Shamu Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Logo Designer / Donating Member Joined: April 25 2007 Location: MD, USA. Status: Offline Points: 20510	Post Options Post Reply Quote Shamu Report Post Thanks(0) Quote Reply Posted: June 23 2023 at 4:24pm
	Oh absolutely! When I got into my accuracy kick with the 101% custom Rem 700 with the Shilen bull barrel & all the other tricks it definitely made a difference! But I was trying to improve on 1/3 MOA! A whole different world.
	Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)

britrifles Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: February 03 2018 Location: Georgia, USA Status: Offline Points: 8404	Post Options Post Reply Quote britrifles Report Post Thanks(0) Quote Reply Posted: June 25 2023 at 6:07pm
	Not quite ready to put the concentricity gauge away yet. I’m going to run one further test. This time with my .308/7.62 loads for my DCRA No. 4 7.62 conversion. The rifle is a Faz 1956 No. 4 Mk2 with a Long Branch made and installed 7.62 NATO barrel. It’s a very good shooter, the most accurate No. 4 I have. It has approx 1500 - 2000 rounds thru it. The reloads I’m particularly interested in are loads I worked up for long range shooting, 800 and 1000 yards. These are long pointy bullets, and seated longer than the 2.80 inch magazine length so that they are within .020 to .030 inches from the lands of the rifling (175 and 168 TMK). Had some time to kill yesterday, so I measured the bullet runout on each of the 50 rounds I had loaded for three different long range test loads: Load 1: Lapua cases neck sized in Lee Collet Neck Sizer Die, 155 Palma MK seated to 2.81 OAL. Average bullet runout 0.0033 inches. Load 2: Lapua cases partial length sized in Lee Full Length Die, 175 Tipped MK seated to 2.935 OAL. Average bullet runout 0.0072 inches Load 3: Lapua cases neck sized in Lee Collet Neck Sizer Die, 168 gr Tipped MK seated to 2.950 OAL. Average bullet runout 0.0033 inches. Similar to the .303 British loads, the lowest runout values were obtained with the Lee Collet Neck Sizer die. Load 1 and 3 had the same average runout, with a minimum of 0.000 inches and maximum of 0.006 inches. Out of 100 rounds, only three had a run out of .006 inches. All three of these loads use Varget powder, with charge weights set according to the bullet weight. They are .308 Win published mid range loads, the maximum I’m comfortable with shooting in my No. 4 and strictly for the purposes of long range target shooting. The Lee FL sizer again gave the largest bullet runout, with a minimum of .002 inches and maximum of 0.011 inches out of 50 rounds loaded; 10 rounds have a runout of 0.009 or larger. I’ve recorded the runout on each round and I’ll be able to determine if it is a variable in individual shot accuracy, and accuracy of the load in general. I plan to go test these loads in the next week or two, and will shoot them at 600, 800 and 1000 yards along with a few sighters at the shorter ranges (100 and 300 yds). I have a Wilson .308 Bushing Type Full Length sizing die and a .308 Wilson In-Line Seater Die but have not tried them yet. That will be the next test. I’m expecting the accuracy edge on the three above loads to go to the 168 TMKs with cases that were neck sized in the Lee Collet die. But what comes in second place, I don’t know…

Shamu Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Logo Designer / Donating Member Joined: April 25 2007 Location: MD, USA. Status: Offline Points: 20510	Post Options Post Reply Quote Shamu Report Post Thanks(0) Quote Reply Posted: June 25 2023 at 6:22pm
	How much bullet full diameter is inside the case neck? I had a similar problem years back with 150 Gr Speers. To get good feeding, jump to lands & so on they had minimal neck engagement. It became a game of balancing choices, seat to lands stand off Vs case neck engagement. Then I just quit using the Speer bullets.
	Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)

britrifles Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: February 03 2018 Location: Georgia, USA Status: Offline Points: 8404	Post Options Post Reply Quote britrifles Report Post Thanks(0) Quote Reply Posted: June 25 2023 at 6:40pm
	Shamu, I don’t recall exactly, but, this was considered when I set the OAL. It’s a trade off as you said. I’ve had good results with the 168’s and 175 TMKs at long range. I68’s were better, but I did not record if the cases were PL or Neck Sized, or new cases… Rule of thumb is to have one calibre of bullet diameter in the neck. But, at the lengths I’m seating these bullets too, I don’t think I achieved that. The secant ogive of the 168’s and 175 TMKs do make these bullets very long for their weight, IIRC, they still have a fair bit of bullet held by the neck.

Shamu Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Logo Designer / Donating Member Joined: April 25 2007 Location: MD, USA. Status: Offline Points: 20510	Post Options Post Reply Quote Shamu Report Post Thanks(0) Quote Reply Posted: June 26 2023 at 10:43am
	That was what I was wondering. What happens if you seat just deep enough to get one caliber in the neck? I ended up favoring that over OAL & the longer jump to the lands.
	Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)

britrifles Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: February 03 2018 Location: Georgia, USA Status: Offline Points: 8404	Post Options Post Reply Quote britrifles Report Post Thanks(0) Quote Reply Posted: June 26 2023 at 1:02pm
	Yes, that is another variable in the load. I did some research on these long secant ogive bullets and the consensus is to seat them fairly close to the lands (around .020 off the lands). The advantage with that is it increases case airspace and reduces peak pressure. You can take advantage of this and increase the charge weight accordingly, but you better know what your doing here… My initial tests with these loads gave very satisfactory results (168 and 175 TMKs) at 800 and 1000 yds, i posted this over on the 7.62 Enfield Forum. Once I determine if bullet runout is a factor in long range accuracy, I’ll probably play with seating depth a bit. These loads however are fairly warm for a No. 4, and I’m mindful of not wanting to wear out this barrel doing this. I think shooting 150 rounds a year is OK, besides, my shooting days with irons are coming to an end, perhaps a few years left. I began this project to see how these DCRA conversions shoot out to 1000 yards, and to see how my own abilities compare with those that came before us.

A square 10 Members Profile Send Private Message Find Members Posts Add to Buddy List Special Member Donating Member Joined: December 12 2006 Location: MN , USA Status: Offline Points: 16998	Post Options Post Reply Quote A square 10 Report Post Thanks(0) Quote Reply Posted: June 26 2023 at 7:31pm
	do you also check bullets for concentricity before loading them ?

britrifles Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: February 03 2018 Location: Georgia, USA Status: Offline Points: 8404	Post Options Post Reply Quote britrifles Report Post Thanks(0) Quote Reply Posted: June 27 2023 at 3:37am
	No, but since these are high quality match grade bullets, it’s highly unlikely they are a source any measurable runout. I don’t think the gage can be configured to check the bullet by itself. I did notice that bullet runout is typically 2x the runout of the case neck. But I think that can be explained by where the runout is measured: at the mid point of the neck along its length and on the bullet approx 1/8 inch forward of the neck. If the axis of the neck is slightly off at an angle relative to the case body axis, then the runout increases the further forward you measure on the cartridge.

Goosic Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: September 12 2017 Location: Phoenix Arizona Status: Offline Points: 8842	Post Options Post Reply Quote Goosic Report Post Thanks(0) Quote Reply Posted: June 27 2023 at 8:02am
	(After the initial case prep has been done.) I have been taking once fired 7.62 Lake City brass and using a Lyman .243W full length resizing die to neck the LC cases down. Each case takes 4 short strokes of the ram to get the desired case formation with the case being rotated 1/4 turn with every throw of the ram arm. After the cases are full length resized I will use a 6mm bronze bore brush on an electric drill and score the inside of the neck. After that has been completed I will run each case through the .243W Lee Collet Neck sizer with a .002" undersized mandrel twice, rotating the case 180°. The brass then gets a 1 hour run through dry media. The final step after being polished has me running the case through the neck sizer one last time. The cases are then primed and loaded with 2.46g/37.9gr of VihtaVuori N540 using a Lyman 2.2g dipper and then scaled out with a trickle charger. The bullet of choice is the HPBT Lapua 6mm 90grn OTM Scenar-L. The case neck concentricity shows zero runout. The bullet seating tension expands the case neck outwards by .003" and allows me to seat the bullets out to 2.710" with zero to .0001" bullet runout. My oldest daughter asked me why it takes me so long to reload 50 to 100 cases. My response was to purposely try to make a question mark after I shot the cartridge case at a distance of 100 yards. The extra time involved with case prep and weighing out each charge is definitely worth the time and effort. The Jap made Weatherby has been taken to Bergers 1000 yard range and produces sub-moa groups consistently and I truly believe that it is due largely in part to the bullet selection, weighing out of each charge and what some would call unnecessary case prep work with me being the redundant component. After the fire formed cases are set to be reloaded, it is then that I use the Lee-Loader "Whack-A-Mole" from that point forward. My daughters targets they shot at a distance of 200 yards for reference......

britrifles Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: February 03 2018 Location: Georgia, USA Status: Offline Points: 8404	Post Options Post Reply Quote britrifles Report Post Thanks(0) Quote Reply Posted: July 05 2023 at 8:37am
	To close the loop on this post regarding effects of bullet runout on the No. 4, I shot my 7.62 reloads for my DCRA 7.62 I mentioned a few posts back. These were Lapua cases neck sized in my Lee Collet die, bullets seated with the standard Lee bullet seater (nothing special here). Average runout for the two different loads were the same, 0.0033 inches with a max of .006 inches. The two loads were with the Sierra 155 Palma MK and the Sierra 168 Tipped MK. I measured and numbered each round and tracked its POI on the target. I could not find any correlation of POI and runout. I thought perhaps at the higher runout values of .005 and .006 might show up as wide shots in the group, but that was not the case. This is the 800 yard target with the 168 TMKs and the bullet runout values for each shot: 1 .003 2 .001 3 .003 4 .004 5 .003 6 .005 7 .006 8 .003 9 .002 10 .003 The two distinct clusters of hits are a result of a change in rear sight windage (PH 5c) by 4 clicks after shot #6. Shot #6 had a runout of .005 and was right in the middle of the cluster of five shots on the left, just outside the 10 ring at 9:00. Shot 7 had the highest bullet runout at .006 inches and it was an X ring shot. Shots 7 thru 10 had no sight changes, and these four shots were within an extreme spread of 4 inches at 800 yards (0.5 MOA group). Looking at shot # 7, 8 and 9, with runout variation of .002 to .006, that three shot sequence in the X ring was even smaller, perhaps 1/3 MOA apart. Note that the grid lines on the target photo represent a 1 MOA grid. My conclusion is that bullet runout of up to .006 inches has no impact on long range shooting results with the No. 4 7.62 barrel. For me, the above result is about as good as I can do with irons regardless, and the elevation spread is likely 90% due to aiming imperfection. The lateral spread is aiming imperfection plus wind affects. I still have the 175 TMK loads to shoot, and these were partial length sized cases with an average runout of .007 inches, max of 0.011 inches; a bit more than double the runout of the above loads. I’ll see how these do next time I get out to the 1000 yd range.

Shamu Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Logo Designer / Donating Member Joined: April 25 2007 Location: MD, USA. Status: Offline Points: 20510	Post Options Post Reply Quote Shamu Report Post Thanks(0) Quote Reply Posted: July 05 2023 at 9:01am
	Great data & reporting. Yeah I quit worrying about tiny variations in run-out & jump to lands a while back now I prioritize bullet seating mostly as it seems to male the most difference.
	Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)

britrifles Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: February 03 2018 Location: Georgia, USA Status: Offline Points: 8404	Post Options Post Reply Quote britrifles Report Post Thanks(0) Quote Reply Posted: July 10 2023 at 7:35am
	Just finished sizing the .308 Lapua brass that I fired in the 7.62 DCRA No. 4 last week. This is the first time using my new .308 Win Wilson Bushing Type FL Sizer Die. I’m quite happy with how this die works. The cases had been neck sized several times and with these moderately high power .308 loads, a fired case shows just a bit of resistance when chambering in the last 1/16 inch of bolt travel (space between bolt handle and receiver wrist). I could have necked sized these cases again, but wanted to try out the new die. I did not “full length size” the cases per se, but set the die position in the press such that the case shoulder was pushed back by .002 inches as compared to the fired case. I did this with the use of a Hornady Case Headspace Gauge, setting the case headspace to 1.626 inches (fired cases measured 1.628 inches). I confirmed by chambering the “partial length sized cases” that the bolt fully locked with only the slightest hint of very light resistance just before the bolt handle touched the receiver. That way, the case head is seated against the bolt head on firing and will minimize case stretch. Checking fired and sized case neck runout on the RCBS Casemaster gauge showed fired case neck runout < 0.001 and sized case neck runout < 0.002, and I’m quite happy with that. I like having the complete control to set neck tension. I sized the first 5 cases using a .334 inch diameter bushing, checked the neck ID with a pin gage and it was a bit small at .3035+, I think that’s more neck interference than desirable with a .308 bullet. The .335 bushing gave me a neck ID of .3050- with that size pin gage, giving a .003 inch interference with the bullet, about just right. Next step is to load these cases up with 168 grain TMKs using the Wilson In-Line Bullet Seater, measuring the force needed to seat the bullets then measure bullet runout. I’m not really expecting these loads to shoot any better than the previous loads with cases neck sized in the Lee Collet Die, but will be happy if they perform equally as well at Long Range. Now, I’m not suggesting you guys need to go run out and get these dies, I did this to satisfy my own curiosity and to fix a significant bullet runout problem that was costing me points with my .223 Rem 600 yard load using the 80 grain SMK. That naturally made me curious if it might improve my 800 and 1000 yard results with the 168 and 175 TMKs in the No. 4 7.62 DCRA.

Goosic Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: September 12 2017 Location: Phoenix Arizona Status: Offline Points: 8842	Post Options Post Reply Quote Goosic Report Post Thanks(0) Quote Reply Posted: July 10 2023 at 8:14am
	Since you have been on this topic for awhile, I decided to truly look into the runout on all of my .243W cases and found that my best cases to work with are my resized to .243W, Norma .308W cases with my actual Lapua .243W cases coming in as a dismal 3rd place contender behind my resized Lake City brass. I started using my Lee Collet Neck sizer again but what I found very disappointing had everything to do with the "Offset" inside the case necks on the majority of the Lapua cases. My BR acquaintance is shipping me his case neck reamer but I am wondering if it is really worth the effort. My range is good for 300 yards but I do not shoot past 200 yards and my Weatherby is as accurate as they come. I'm going to use the reamer on a batch of 50 cases but anticipate little to no improvement over the unreamed cases. What say you on this Geoff? I had my daughter shoot this group at 200 yards using the 25 yard slow fire pistol target because of how well the nice bright red center shows up in the scope. All the cases pictured are the unreamed Lapua cases...

britrifles Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: February 03 2018 Location: Georgia, USA Status: Offline Points: 8404	Post Options Post Reply Quote britrifles Report Post Thanks(0) Quote Reply Posted: July 10 2023 at 8:31am
	Not sure what to suggest Michael. Lapua is generally very good brass. In the sample of .223 and .308 new cases I checked, neck runout measured less than .001 inches. And yes, I think if the neck is out of alignment going into the Lee Collet Die, it will come out that way too since only the neck is touched by the die. I found that my DCRA Long Branch barrel chamber neck is slightly off center with the axis of case body. A new case measuring zero runout comes out after being fired at .001 inches. All the fired cases measured .001. So, neck sizing these in the Lee Collet Die also gave .001 neck runout. I think this is still very good, and nothing to worry about. My conclusions so far shooting the No. 4 .303 and 7.62 is that bullet runout as much as .006 is completely undetectable in the 7.62 out to 1000 yds and as much as .010 in the .303 was not detectable at 200 yards on the target. .010 however on my .223 at 600 yards was a definite problem for me and the Wilson dies solved that for me. Check the neck runout on some of your fired cases, if the neck of the chamber is concentric with the body area, the runout should be less than .001, since the fire formed cases should be the shape of the chamber (with a slight bit of spring back).