Video On Bump sizing cases.

It appears to me that everyone has the same goal to load more accurate ammo. That means more accurate on the target. Some people are willing to go to every extreme what ever that is to get a bullet to land as close to POA as possible. Some people fully prep brass and weigh sort all components. Some don't because they can't see the difference on target. I have too shot my very best group with neck sized brass but I was never able to repeat it. So I started looking for a better way hence why I joined this group.
Now I fully prep my brass and after firing I bump FL size my brass to fit my chamber with no bolt resistance which is about .002 shoulder bump.
If something else works them that is awesome and more power to them. Like JE said it is what works for me that counts. The two above videos show two different ways to size brass based on each presenters experience.
I also think we may be talking about two different types of shooting.
Most long range shooting matches require a lot of rounds down range in a single day. Obviously they don't load on the range like BR shooters do. It stands to reason that lots can change during the course of a day. Temperature, wind, dust, sun on your gun for part of the day, etc, etc, you get the picture. To load a batch of ammo that will only fit one condition would not end well at the end of the day long match. So he will FL size his brass with a .002 shoulder bump so it will fit the chamber all day.
If just the smallest group one time is the goal then most will neck size only and some don't even size the whole neck so it will align with the chamber perfectly.
As hunters we want to be able to shoot when ever the game presents its self whether that is early morning at 10*F or in the afternoon sun at 50*F or in the snow or rain. So most of us bump our shoulders so the ammo fits all the time. Is that the most accurate period, I can't answer that question because I will not chance it. I have on two different occasions seen necked sized brass not function in a firearm while a big buck was standing broadside to the frustrated hunter.
I will say that once that bigngreen built me a precision firearm then the burden was on me to load ammo that would let his precision work shine.
All this talk of precision reloading and slight differences in sizing Technics is for naught if the chamber is not straight with the bore.
One last thought is that since pressure is equal in all directions a little clearance is OK to help the case align with the chamber as it expands.
 
Do you trim a fired case or a sized case. I trim a fired case.
I need to learn how to use a sizing mandrel. Haven't ever used one. I understand the method might help me eek out a bit more accuracy.


Yes,
I find that I must trim first (Necessary to accurately turn the neck) I can also check to see how much growth the case experienced the first time and use it as a base line for trimming in the future if they need it. This is another area that minimum sizing paws off. the less you size the less case length growth you will see.

J E CUSTOM
 
Oh yha,,, I hear brother,,, thanks again for sharing in ideas for those of us who choose to give things a try...

Glove fit,,, less run-out is what I'm after...

I got a chance to send some sctechy bullets down range 5 years ago,,, i must of learned something since things have improved alot since then...

Its always refreshing to re-schooled on the stuff that has slipped my memory,,, threads like this get me back into grove... Ha...

I have always enjoyed following along with you JE,,, you've definitely put in the time to assist many of us over the years... 2 thumbs up brther...

Always pal Don from North of the 49th
 
The best part about reloading is the person pulling the press handle decides how to do it.

I prefer bumping the shoulder back far enough to give me some head clearance. And this method also takes the load off the bolt lugs when closing the bolt and prevents galling the lugs. This also reduces the bolt thrust because the case must stretch .001 or .002 before contacting the bolt face. Meaning the case acts like a shock absorber and reduces the dwell time the rear of the case is contacting the bolt face.

So all of you who prefer snug fitting cases I hope you grease your bolt lugs to help prevent galling the lugs.

Below there is nothing wrong with a few thousandths head clearance. The ejector will push the case forward in the chamber along with the firing pin hitting the primer and this reduces the load on the bolt face, locking lugs and the amount of dwell time and bolt thrust.

HK76WCp.jpg
 
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This brings up another question...

What the forward and rear-ward movement of the bolt in the action...

I guess I'll need to set up the dial indicator to check all 3 of my rifles...

I bet 10 to 1 that they are all different with and with out firing pin,,, and with some snugg fitting catridges...

I'll have to run a few snugg fitting catridges to get an overall measurement number...

Rear bolt lug kick-up as well... ha...

More of a fun thing to see what the numbers are...

I'll see if the """inner""" inside of the bolt handle is making contact or not at the rear action cut slot too...

I'll get my Machinist friend to help me figure this out since he knows all these measurement angles...

It will be interesting to know how much play is on the bolts in the actions...

I guess we will all find out if there """is or isn't""" play between the bolt shank and actions on my 3 rifles... Ha...
 
I do notice when I bump shoulders, there's always a few cases that chamber harder than others. It doesn't matter if I'm using my CO-AX or rockchucker, its in every cartridge I load for. Redding dies or lee dies, it happens. I anneal and prep cases pretty meticulously, and it's still there. Sometimes it equates to a flier and sometimes not. I got a new a new lot of star line 6.5 creed brass I'm getting ready to prep. I'm going to give this a try with 50 or so cases. I always have a open mind, and when Jerry says something works, I'm inclined to believe him. It's worth a shot, just going to keep my bolt lugs greased.
On cases not getting the same bump, of coarse uniform lube helps. I run into this too, and keep a whidden case gauge right beside my coax when sizing, easy to measure. Most of the time, with a coax, not sure on a RC, you can feel the difference of a case taking the bump or not, feel it when you pull the handle back up, there is a drag. I usually just rotate the case 120 deg or so and re-run it into the die.
I had watched this vid before, and there are a couple things said that I did not agree so I discount most he has to say. He lost me on keep sizing one pc of brass till you get it right, then your die is set, NO, your die is set for that pc of brass only..
I strive for a minimal bump, keeps the flow going, tight in, tighter out. Even though I do have a tube of grease in my range bag, I prefer not to pull it out to grease bolt lugs.
I have a SA Defiance Deviant with the right bolt lug galled, the face in the action where it mates up is galled too. 2500 total rds fired. I'd love to sell it and replace it with an Impact 737, but in good faith I cannot do that. It is mine till I croak, either in moth balls or in service.
 
This brings up another question...

What the forward and rear-ward movement of the bolt in the action...

I guess I'll need to set up the dial indicator to check all 3 of my rifles...

I bet 10 to 1 that they are all different with and with out firing pin,,, and with some snugg fitting catridges...

I'll have to run a few snugg fitting catridges to get an overall measurement number...

Rear bolt lug kick-up as well... ha...

More of a fun thing to see what the numbers are...

I'll see if the """inner""" inside of the bolt handle is making contact or not at the rear action cut slot too...

I'll get my Machinist friend to help me figure this out since he knows all these measurement angles...

It will be interesting to know how much play is on the bolts in the actions...

I guess we will all find out if there """is or isn't""" play between the bolt shank and actions on my 3 rifles... Ha...


With just the bolt in the receiver it is normal to have .007 to .010 thousandths slack forward and backwards. Some have even more than that depending on how much bolt relief was built in. This is still OK as long as it is not caused by bolt lug set back from hot loads.

When you place a go gauge in the chamber with no firing pin assembly and ejector, the centerline movement should be held to .003 to .004 maximum. Best is .0005 to .0015 in my opinion. After fire forming, it should be .000 and adjusted to what you prefer during sizing. The amount of head space needs to be based on the type of firearm and it's use. When possible, I prefer .000 to .0005 to hold the bolt stationary during firing (No Slack).

J E CUSTOM
 
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On cases not getting the same bump, of coarse uniform lube helps. I run into this too, and keep a whidden case gauge right beside my coax when sizing, easy to measure. Most of the time, with a coax, not sure on a RC, you can feel the difference of a case taking the bump or not, feel it when you pull the handle back up, there is a drag. I usually just rotate the case 120 deg or so and re-run it into the die.
I had watched this vid before, and there are a couple things said that I did not agree so I discount most he has to say. He lost me on keep sizing one pc of brass till you get it right, then your die is set, NO, your die is set for that pc of brass only..
I strive for a minimal bump, keeps the flow going, tight in, tighter out. Even though I do have a tube of grease in my range bag, I prefer not to pull it out to grease bolt lugs.
I have a SA Defiance Deviant with the right bolt lug galled, the face in the action where it mates up is galled too. 2500 total rds fired. I'd love to sell it and replace it with an Impact 737, but in good faith I cannot do that. It is mine till I croak, either in moth balls or in service.
When I first got into reloading belted cartridges, I had a Vanguard in 300 Weatherby. I was so worried about case separation and losing expensive brass, I neck sized only. I too have the right lug severely galled. It literally had a sharp burr that would cut you.
 
When I first got into reloading belted cartridges, I had a Vanguard in 300 Weatherby. I was so worried about case separation and losing expensive brass, I neck sized only. I too have the right lug severely galled. It literally had a sharp burr that would cut you.


I guess I am lucky because I have never had a bolt lug gall. I have seen lugs that were very bad that needed to be leveled and squared to prevent this. when I blueprint an action after leveling and squaring, I polish both surfaces with 1200 or 1500 Garnet lapping compound. This makes the lugs very smooth and prevents galling.

Neck sizing can help prevent this but high pressure loads and heavy bolt lift are the biggest reason that galling occurs.

J E CUSTOM
 
Let me just say this. How tight or how much tolerance you have between your chamber wall and your brass has very little to do with making a rifle shoot. What is important is that everything from your bolt to your chamber to your barrel is in perfect alignment and your ammo is straight. The bullet is going to engage the throat, rifling before it leaves the case neck. That is why all these competition guys are so anal about loading ammo with very little runout. The rat turd in a violin is of course an exaggeration. Their view is that they did not want the chamber or neck putting any undue stress on the case, bullet to put it out of alignment with the bore. Obviously .002 clearance is not a sloppy fit. And of course excessive resizing can cause headspace issues. Imho it's more important to have straight ammo and a straight chamber with zero runout to the bore axis.
I concur
 
With just the bolt in the receiver it is normal to have .007 to .010 thousandths slack forward and backwards. Some have even more than that depending on how much bolt relief was built in. This is still OK as long as it is not caused by bolt lug set back from hot loads.

When you place a go gauge in the chamber with no firing pin assembly and ejector, the centerline movement should be held to .003 to .004 maximum. Best is .0005 to .0015 in my opinion. After fire forming, it should be .000 and adjusted to what you prefer during sizing. The amount of head space needs to be based on the type of firearm and it's use. When possible, I prefer .000 to .0005 to hold the bolt stationary during firing (No Slack).

J E CUSTOM

if you place a NO-GO gauge in the chamber this gauge on average is approximately .003 longer than the GO gauge. And on a new rifle, the bolt should not close, meaning anywhere between GO and NO-GO on a new rifle is normal. From there for wear and usage, you have a Field Gauge allowing .007more headspace.

The ejector pushes the cartridge forward with no centerline movement and the firing pin hitting the primer can make the case even shorter. Meaning between the ejector and the firing pin the case shoulder is being forced into the shoulder of the chamber. And after firing and brass spring back there should be no excessive effort opening the bolt.

And there is no reason for the rear of the case to be pushing on the bolt face. You are not lapping your lugs so why apply pressure to the bolt face. This is why the thumb rule for bumping the shoulder back is .001 to .002 on a bolt action when full length resizing.

So how many of you grease your bolt lugs to help prevent galling? And how many of you know why the headspace increases on used rifles, meaning lug wear or lug setback.

Below the rifle, I own that allows me to easily change the headspace by changing the bolt head. And I sure do not want excessive force closing the bolt with the possibility of galling the lugs and increasing lug wear.

v1GFvaK.jpg



Pacific Tool and Gauge offers three lengths of headspace gauges per rifle caliber. In order from the shortest to longest, they are: GO, NO-GO, and FIELD:


GO: Corresponds to the minimum chamber dimensions. If a rifle closes on a GO gauge, the chamber will accept ammunition that is made to SAAMI's maximum specifications. The GO gauge is essential for checking a newly-reamed chamber in order to ensure a tight, accurate and safe chamber that will accept SAAMI maximum ammo. Although the GO gauge is necessary for a gunsmith or armorer, it usually has fewer applications for the collector or surplus firearms purchaser.

NO-GO: Corresponds to the maximum headspace Forster recommends for gunsmiths chambering new, bolt action rifles. This is NOT a SAAMI-maximum measurement. If a rifle closes on a NO-GO gauge, it may still be within SAAMI specifications or it may have excessive headspace. To determine if there is excessive headspace, the chamber should then be checked with a FIELD gauge. The NO-GO gauge is a valuable tool for checking a newly-reamed chamber in order to ensure a tight and accurate chamber.

FIELD: Corresponds to the longest safe headspace. If a rifle closes on a FIELD gauge, its chamber is dangerously close to, or longer than, SAAMI's specified maximum chamber size. If chamber headspace is excessive, the gun should be taken out of service until it has been inspected and repaired by a competent gunsmith. FIELD gauges are slightly shorter than the SAAMI maximum in order to give a small safety margin.
 
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