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.270 Win Concentricity, simplicity lesson learned...

22 Nov 2018
@ 11:25 am (GMT)

Robert McLean

So my reloading experience is all of about 100 rounds. Just to get that out of the way first...

My kit is a set of used Lee Ultimate Dies, a Lee Cast Press, a Sinclair concentricity gauge and assorted other tools, many that came to me in a trade.

It really just depressed me for the first 75 rounds. I am just using winchester X 150 cases that I used to break in my gun. My Neck sizing die was producing a run out anywhere from 1 to 7 + thousands and then a run through my seating die would produce anywhere from 1 to 20 thousands. Yikes, I didn't even try to fire some of them and actually some would not even chamber.

Well, I searched through the forums and finally it came to me after reading many many things. Clean the equipment dumb ass and pay attention to the cleanliness of the case and bullet. So I cleaned my seating die and the shell holder, yes the shell holder because it was full of crud under the rim. Everything is nice and shiny and loose now. I really paid attention to the case neck inside and the outside of the case as well. Well I did a set of 12 with my lowest run out neck sized cases and lo and behold run out was from 1 to 3.5 thousands after seating. Miraculous...

So I thought. well I did use my best sized cases with just 1 and 2 thousands run out so maybe that led to the great outcome. Of course that makes sense... So I need to do it again and this time clean the neck die... I ran some more cases through the neck die and poof I got way more cases around the 1 thousand run out range. Found 12 that were that good and ran them through the seater and I got 1 - 3 thousands run out with my batch last night.

I am really taking my time with the press when I am seating so that may help to. Turning my case as I go along in the press and slowly going to the OAL i want.

I was so close to buying fancy dies because obviously that was the issue...

Not so much.

I still have things to work on but I just thought I would share...


27 Nov 2018
@ 11:06 am (GMT)

Joshua Mayfield

Re: Concentricity simplicity lesson learned...
That's a good post, Robert. I have been learning since I began reloading that the answer to an issue is usually fairly simple, though sometimes hard to identify. There's a lot to be said for slowing down and just making sure tools and equipment are in proper order and condition. It sure is tempting, when results aren't what you'd hoped for, to assume the answer is more expensive equipment. I was really flirting with a pricey set of dies myself before Nathan's reloading book arrived in the mail. Thank goodness for that book. The cost of the book was paid for very quickly in equipment I realized I did not need to buy.
27 Nov 2018
@ 04:27 pm (GMT)

Paul Leverman

Re: Concentricity simplicity lesson learned...
Well done, Robert. Another area you may want to consider is the lube you are using. Imperial wax is great, but so are others. You don't want to stress or cause your brass to become misshapen by not enough or poor quality lube. Another good point is one you made: "I am really taking my time with the press...". That in itself will give good results.
28 Nov 2018
@ 08:03 am (GMT)

Robert McLean

Re: Concentricity simplicity lesson learned...
Ya, I am finding that the old tube of Lee sizing lube that came to me when I traded for a bunch of loading stuff is pretty watery and just plain nasty to use. I don't have any neck lube yet, ordered some graphite. I think i will try the imperial wax for case lube.

It really does pay to be slow and steady with the press. It is actually taking me several passes to get to my OAL. I am getting really good concentricity results. The one issue I am having is getting that consistent OAL within 1-2 thousands. Using so many passes is meaning that i am measuring and going back to the press alot and then suddenly I am a couple of thousands short. I have to work on solving that.

I am also still getting used to my collet neck sizing die. Need to get that consistent weight on the handle. My internal neck sizes are not greatly consistent going from .272 to .275 inside. I am wondering about that die. It should not be producing tight necks like that when the mandrel is .275 according to my caliper.

I am not sure this makes much difference in the end but it must have some affect because with the tighter neck there is more resistance, leading to more thousands out possibly. Every 1/1000 counts...

I think it maybe be my 'inexpensive' caliper giving me inconsistent readings all around. Measure twice, calibrate four times is an understatement with this thing when I am dealing with thousands. I only paid $20 for it and being digital it jumps around alot. I am cheap, but I am thinking an investment in a Mitutoyo is worth it for my piece of mind.

28 Nov 2018
@ 08:09 am (GMT)

Robert McLean

Re: Concentricity simplicity lesson learned...
Thoughts on digital calipers?

My eyes are not so good close up so I am using a big lighted magnifying glass alot. The Mitutoyo 500-196-30 is a digital absolute version at about the same price as the Mitutoyo 532-120 Vernier Caliper. Never used a vernier but it sure does seem like it will make my eyes work hard.
28 Nov 2018
@ 10:48 am (GMT)

Joshua Mayfield

Re: Concentricity simplicity lesson learned...
Hi Robert,
I haven't tried a digital caliper. My vernier is pretty cheap but I've felt good about it. I do think that if some extra money toward acquiring a tool that has a sterling reputation helps us be able to eliminate one variable (not blindly, of course - everybody has a dud now and then) then it's a fair investment.

On the case lube topic, I started out with a homemade lube that the internet told me would solve all my problems and change the oil in my truck too (slight exaggeration). After a couple of stuck cases I grabbed a tub of Hornady's Unique Lube and I am completely happy with it. I've not had a single issue with cases getting stuck, or even close, and the lube rubs on and comes off easily. It doesn't smell offensive either. I've never used some of the other popular lubes and am happy enough with the Hornady that I probably never will.
28 Nov 2018
@ 12:34 pm (GMT)

Paul Leverman

Re: Concentricity simplicity lesson learned...
I could be wrong here, and I hope someone who knows better will educate both of us, but I think you are overthinking the OAL. If the neck is long enough to ensure concentricity (guidance) for the round, then being one or two or even five thou out isn't going to make that much difference, as long as it's not overlength. But like I said, I'm not positive on this.

Have you checked your neck thicknesses? The spring-back in the brass may be causing the differences. A thick neck will still pass over the mandrel and not really be sized and when withdrawn, the brass just relaxes back to where it started.

Just some thoughts.
29 Nov 2018
@ 05:54 am (GMT)

Paul Leverman

Re: Concentricity simplicity lesson learned...
Yeah, sorry Robert. I misunderstood your OAL reference. I thought you were talking about your cases, not your loads.

Pull your seating die apart and try your bullet in the seater plug. It should fit without a lot of wobble, and push on the ogive, not the tip. The difference in tips could be the root of the problem.
29 Nov 2018
@ 06:28 am (GMT)

Robert McLean

Re: Concentricity simplicity lesson learned...
Nope haven't gone there and neck thickness could be an issue with these Win cases. It does seem to be very stubborn on some cases. I have reloaded some of them 4 times now too so unless I am wrong that causes them to harden a bit?

I agree on the case length being not as important maybe, I do fixate on consistency in everything. I am going to play with case length this week a bit.

I am having issues getting that magic finished cartridge length right on to what I am looking for. So bullet jump becomes an issue on my mind.

I am really grabbing at straws each week in so many facets of getting accurate results. This last week it was my caliper accuracy was frustrating me so that became the focus.

I am getting to where my groups are good but never three touching and boy I hate fliers. It is all shooting technique practice if nothing else right? My game is way better than a year ago before i bought the books and read for hours on here...

I think I just need more hours and more shots.

I go shooting on Saturday's and if the weather and wife are co-operating I get in 20 rounds of .270 and a 100 22lr. Its getting so I will need my chains soon to get down to the range. I need another hobby for the winter or it could get weird at -30 with 3 feet of snow.
Fly tying sounds good, I lost alot of those last year...

29 Nov 2018
@ 01:11 pm (GMT)

Paul Leverman

Re: Concentricity simplicity lesson learned...
If you have enough cases, just set the difficult ones aside for now. They could be work hardened and need annealing. Concentrate on the easy and when you have more time available then you can try annealing some of them and see if anything changes. Just load and shoot for now before it's too late, it already is here.

I purchased a set of electronic verniers from Frankford. They seem to do alright, nothing fancy, but reliable and easy to read. The first set I bought went all weird anytime they got under the fluorescent lights, but Frankford replaced them no questions asked.

30 Nov 2018
@ 06:29 am (GMT)

Robert McLean

Re: Concentricity simplicity lesson learned...
Ya, I am trying to get over a hump where I don't know what is holding me back . It could be so many things and is probably a combination. I am under MOA pretty regularly but I just can't get to .5. Powder, cases, bullets, loading details, shooting technique, stock, barrel, scope, bench, rest and on and on.

I may not even have a barrel that is capable. It collects copper on the lands like nobodies business. I am wondering if it is a slightly tight bore. I have been giving it a dose of JB paste every cleaning for the last few.

Now looking into a Chronograph. Haven't even gone there yet, the building we are shooting out has an overhang. Supposedly a normal chrono doesn't work well. Guys have this Lab Radar Ballistic Velocity set up, $700. I have found a modified a Caldwell Chrono that reads Sound instead. I wonder if anyone has looked at one of these. Not much info out there on it.

Paul, you in the north too? I am in Red Deer, -12 this morning. The range is pretty good for winter shooting, there is a room with a wood stove to warm up in. The only downfall is no real decent set up for prone shooting. I have never been able to shoot in the winter. The road down into the valley is steep and is going to get sketchy. I will need chains at some point but I don't plan on giving in.
30 Nov 2018
@ 08:06 am (GMT)

Hamish Gibbs

Re: Concentricity simplicity lesson learned...
Hi Robert thanks for sharing your trials and tribulations certainly gives one to think about.
Is it possible an indoor lighting kit fixed to a standard chrony would give more consistent results under that overhang than a chrony relying on inconsistent environmental lighting?
30 Nov 2018
@ 09:03 am (GMT)

Nathan Foster

Re: Concentricity simplicity lesson learned...
Hi Robert, it sounds like you are going quite well.

Yes, if you are becoming long sighted with age, a digital Mitutoyo or magnifying glass can help.

Do try to keep things simple. Note the video I put up a few weeks back. This was very much the same. The client used the books to make sure the rifle was correctly fitted in the stock (1 oclock test, rifles book), he then addressed the bore (three sessions as per accurizing book / stubborn fouler), then got stuck into his hand loading. But it was at this stage that he became unsure (is it me, is it my rifle).

Do not try and get all bullets to the exact same OAL. Use one test bullet to measure the max OAL for the rifle, then use that same bullet to set up your seating die then perhaps one more bullet of the same dimensions (record these dimensions in your journel) to seat one more bullet. After that, do not take any more measurements. You did not mention the cartridge but you did mention the mandrel at .275" so I will assume this is a .270. In some instances, a .270 won't let you get close to the lands. If the throat of your rifle is long, don't try to chase the lands if it puts the bullet so far out of the neck that there is a risk of the ammo being poorly supported or at risk of being bumped out of concentricity during feeding. Also, if the jump is long, then stay clear of all short bullets. Go with 150gr weights only. This will even out the pressures during ignition. Plus, the long throat will allow high velocities.

Like the .30-06, the throats (free bore) on the .270 vary a great deal (.120" or more) so you must treat each as unique.

Powder charges are also unique to the bore. In one rifle, max pressures may occur at book max. In another rifle, book max may perform like a down load.

Sweet spots will occur at various nodes. There will be a soft load sweet spot and a high velocity sweet spot. Quite often, the .270 performs best when driven at full speeds. Yet few people actually load to these speeds. Most use burn rates that are too slow to reach full power.

Regarding brass, take the fired cases and run them over the Sinclair. If the Sinclair is showing high run out on the fired cases, then try a batch of Hornady brass. But from what you have described (inside .003") there are no issues here.

Common .270 issue scenarios:

Guy buys .270, starts hand loading. Hand loads go OK, acceptable accuracy, nothing fancy. Guy decides to hot things up, push things around a bit. Several issues start to occur. 1, wrong powder, does not reach full speeds / upper sweet spot. 2. Guy uses H4350 or similar, reaches full speeds but the rifle now recoils a great deal and both the bedding and the shooter are unable to manage this power level. This is then misinterpreted as being "too hot", poor accuracy blamed on the powder charge. 3. Guy uses 130gr SST, finally gets it up to speed, only to have bullet blow up on impact on large deer. This can be classed as poor utilization of power (speed without momentum). 4. Rifle throat leade angle not ideally suited to bullet being used, mechanically handicapping the rifle (discussed further below). This is a more complex issue. As an aside, this is an issue that needs to be considered when trying to make the .270 perform at very long ranges. Many of us (me included) want better long range bullet options for the .270 but we often fail to understand that the chambers are designed for certain bullets (designed many decades ago). There is a point where we have to face the fact that this bore / chamber design can only take us so far. Ridge to ridge - yes. New world record with $600 rifle - possibly no. Not all rifles will take us below sub half minute with the bullet we want to use.

A chrony can help when you are learning. I think an important factor is to realize that you have done very well to get the rifle shooting inside the MOA mark. That is a very good achievement. But if you want to take it further, you might have to approach loads as though starting over. Utilize the same methods, but pay attention to the OAL, the bullet weight, powder burn rate and potential velocities, knowing that as you go up in recoil, it will have an effect on you and the rifle. This last couple of hundreed feet per second and last .3 MOA can take a bit to work through. Go easy on yourself.

Example of generous throat: 150gr SST, max OAL around 3.42 to 3.46"
Short throat: 3.307 to 3.34" .

If using SST, try seating on the lands. Just in enough that the bullet does not get stuck during extraction. You cannot use a bullet comparator for determining this, must use a partially neck sized case to obtain the exact max OAL and seat to this or perhaps a couple of thou in. Why- because the throat design of the SAAMI spec reamers are not perfectly suited to the SST and this method will cause the least upset. Plus, the 150gr SST can be made to both reach to the lands in a long throat gun yet still fill the case neck. Work up loads carefully after this as it will have an effect on pressures.

If the above fails, jump at 40 thou and retry.

If you have a good handle on technique, good bedding and the SST still won't go below .7" then start over with the Speer or Partition. Don't keep chasing the SST by bringing in new powders. Too often, a guy will quote striking gold after trying several powders when other factors are at play and the node is in fact inconsistent (too much to discuss here).

If using the 150gr Partition (good bullet for your neck of the woods), jump at 40 thou. Do not chase sub half minute as you do not need it, just try to get close to a half minute. Accuracy will fall away at the same range as bullet performance falls away, no need to chase accuracy further.

If both fail, switch to Speer 150gr bullets. The Speer may allow you to get below a half minute if others won't play ball. Try 20 thou jump.

Pressures: If you seat close or on the lands, it raises pressures. As you seat back, it reduces pressures. But as you seat even further back, reducing case capacity / powder space it once again raises pressures.

It will be very difficult to develop loads at this time of the year unless you can keep your ammo at a good temp. Suggest you place ammo in a slightly warmed insulated bag, just enough to mimic fall conditions. After load development, you can test the same ammo cold over a cold bore, check the POI etc.

Hope that helps. Its a lot of info, don't let it overwhelm you. Remember, you have done well. Take any further steps at your own pace. Don't feel that you have to live up to an expectation of sub half minute as some factors will be more difficult to control such as overcoming leade angle issues. So in saying this, don't let others confuse you with irrelevant input.
30 Nov 2018
@ 11:22 am (GMT)

Robert McLean

Re: Concentricity simplicity lesson learned...
Wow, thanks Nathan. It is a Weatherby .270, 24" barrel, wood stock, front and rear weakly bedded and barrel floated. I had it done before I found your site. Passes the 1 o'clock test and is shooting sub moa so i am not messing with it anymore. I plan to wear it out so I can justify a new one.

I will have to read this a few times to get it all soaked in. I have read your books ragged, so I am used to reading things over and over.

Hamish, never even thought about artificially lighting up the crony.
04 Dec 2018
@ 07:21 pm (GMT)

Hamish Gibbs

Re: Concentricity simplicity lesson learned...
Robert. What I should have said. "If the issue with a standard screened chrony is the lighting under the roof overhang then there are chronograph lighting kits available"
Some people with permanent setups will fix the screens into a light box or tunnel with artificial lighting.
Looks like Nathan has given you some homework! Good luck and enjoy.
08 Dec 2018
@ 09:32 am (GMT)

Nathan Foster

Re: .270 Win Concentricity, simplicity lesson learned...
Hi Robert, just a quick note, I have changed the heading of this thread slightly so that other .270 users can browse the SST / chamber info.

For other readers (Tikka shooters):

Example of Tikka chamber / 150gr SST / Max OAL sometimes around 86.2mm
or 3.393". This should be considered somewhat short.

Magazine length 85.7mm (3.374").

Seat to 85.2mm (3.354') and see how ammo feeds. Seat shorter if need be.

Work up loads very carefully, no assumptions. H4350 / 2209 / N160 still best, especially for this reduced volume. Hope for high (cartridge book) speeds (possible in some of these rifles) but if the rifle is slow (also taking 22" barrel into account), so be it.
16 Dec 2018
@ 03:11 am (GMT)

Paul Leverman

Re: .270 Win Concentricity, simplicity lesson learned...
Sorry, Robert. Somehow missed your question. True North, strong and free. Prince George, BC.


We are a small, family run business, based out of Taranaki, New Zealand, who specialize in cartridge research and testing, and rifle accurizing.