Video On Bump sizing cases.

[RYEWSKY25284]

Very interesting. When fitting the case to the chamber with the bolt, does the firing pin need to pulled out so you are not feeling the spring tension of the firing pin?

I was taught to pull the firing pin out of the bolt so I can feel no resistance when closing the bolt.

Jason

Not the firing pin, but the ejector plunger. The spring loaded ejector plunger will give you a "false feel" of tension when closing the bolt. You will ultimately get the correct feel after you remove the plunger.
This is how I was taught.
Great Video.
Thank you JE Custom

 

[Frank Kalisz]

I have a slightly different take on bump sizing.

I started my handloading by only neck sizing, but I found I had a chambering problem with a few rounds after I reload the brass a couple times.This is obviously unacceptable for hunting so I learned about bump sizing with hornady comparators and redding "competition" shell holders.

I decided to keep it simple with only 2 goals - bump by only the minimum amount that I can detect on my caliper (typically 1 thou), and try to make all my sized brass identical. So all I had to do is separate all my brass by headstamp and date, make sure I always do identical annealing on all brass specimens, and consistently use the proper sized shellholder that gives a slight movement on my caliper with comparator on it. I never have chambering problems now and they seem to work well. So am I making it too simplistic?

 

[Beluebow]

Also when fire forming an AI cartridge it is common place to have a .004 to .006 negative head space that Places the bolt in compression? it is to hold the cartridge so there is no forward or backward movement during fire forming and producing accuracy that many times exceeds the accuracy of a cartridge that Is full sized for a standard chamber and has "Slop In the chamber fit".

That is a opinion and hardly a fact...it's more about the gradual pressure curve during the fire forming process than a tight bolt close holding a case in place. Yes it is hard to replicate a GOOD fireforming load with the same powder charge and velocities.....but it can and is easily bested with full power loads and formed brass, a quick look at long range records over a couple disciplines will tell you this. Or just ask any Dasher/BRA shooter.

 

[bigedp51]

Just something to think about. Why go to all the trouble to blueprint an action. load concentric ammo and feed it sloppy fitting cartridges. Also when fire forming an AI cartridge it is common place to have a .004 to .006 negative head space that Places the bolt in compression? it is to hold the cartridge so there is no forward or backward movement during fire forming and producing accuracy that many times exceeds the accuracy of a cartridge that Is full sized for a standard chamber and has "Slop In the chamber fit".

J E CUSTOM

I have had brand new unfired cases that were .009 shorter than the GO gauge.

Please tell us how you would get .004 to .006 negative head space with a new case shorter than the chamber.

And again benchrest shooters today do not want tight fitting cases in their chambers. This is because the rifle will shift position on the bags when working the bolt that effects the group size.

What you are saying is the complete opposite of what competitive shooters are now saying and doing at accurateshooter.com/

 

[J E Custom]

I have had brand new unfired cases that were .009 shorter than the GO gauge.

Please tell us how you would get .004 to .006 negative head space with a new case shorter than the chamber.

And again benchrest shooters today do not want tight fitting cases in their chambers. This is because the rifle will shift position on the bags when working the bolt that effects the group size.

What you are saying is the complete opposite of what competitive shooters are now saying and doing at accurateshooter.com/

You wouldn't/shouldn't have cases that short, but if you do you should seat the bullet against the lands with reduced loads to hold the head space in reasonable tolerance.

Most good quality cases are within a few thousandths of the SAMMI chamber dimensions unless the chamber is cut to deep.

I have heard the stories of how many experts full size and have shot against many state and national champions and learned at an early age not to believe anything they said because most are not willing to tell you the truth how they do everything because they want to keep their status
and don't want to help their competition to become better than they are.

I used to enjoy watching the younger/newer shooters gather around these guys like school kids and believe everything they said (I had fell for it but learned better. So even though I admired their shooting skills, I learned to pay little attention to what advice many of them would share
And If I was unsure. I would try it my self In test and practice and not get caught with egg on my face at a match.

I won many matches because people would listen to some of the misleading information and show up at the match armed with all the latest tricks, only to fall flat on their faces because they didn't try/test it out before the match. I also saw many cases of deception by some of the top shooters, that was overlooked because they were who they were. many of these top shooters would find loop holes in the rules and use them to there benefit. Competition will cause people to do many questionable things so all a person can do is follow the rules and enjoy a win when it comes.

I know that it sounds cynical But when I started training as a craftsman I soon learned who would share good procedures and who wouldn't, and saw this in many other skills over my lifetime.
I have no preconceived notion or expectations that everyone will convert to my way of thinking or doing, and don't try to change them, they are the only ones that can effect changes for them. So all I can do is pass on what works for me, not what someone tells me or I heard on the internet.

Also, Shifting on the bags has nothing to do with the precision of the rifle or the ammo, It has everything to do with shooter skills. If the shooter is not consistent, the finest rifle and ammo in the world can't make him a High master.

What ever a person believes is his choice and he has to except the outcome. Whether or not one method is better that the other, I just can't make my self do anything sloppy. As a craftsman I was taught to do everything better than the last time and this philosophy has served me well.

Just My Opinion

J E CUSTOM

 

[YZ-80]

Thanks, JE. Very informative and useful information. The Cameo appearance by Fog-Horn, Leg-Horn was icing on the cake!

 

[J E Custom]

That is a opinion and hardly a fact...it's more about the gradual pressure curve during the fire forming process than a tight bolt close holding a case in place. Yes it is hard to replicate a GOOD fireforming load with the same powder charge and velocities.....but it can and is easily bested with full power loads and formed brass, a quick look at long range records over a couple disciplines will tell you this. Or just ask any Dasher/BRA shooter.

Po Ackley believed it and proved that by compressing the parent case .004 to .006 while fire forming produced the best results forming the cases and the accuracy was better at this stage of firing. The end results after complete case prep is concentric cases if the chamber is concentric. The best fire formed case will always out perform the fire forming load but this process is a way to utilize the parent loading with good usable accuracy to avoid wasting components just to fire form cases.

J E CUSTOM

 

[Don A Parsons]

My newer 6.5/06,,, A-Square is kind of on board with partial full-length sizing...

It seems like only 2/3rd of the neck gets sized """if""" I set the die to not touch the case walls just above the bottom web or shoulder...

The fired cases fit into the chamber with no chamber contact with the firing pin removed from bolt...

The bolt handle drops free with the shot spent cases,,, so i kept turning the sizing die down till I could feel resistance of the handle,,, the bolt handle would stop at the 3 to 9 O'Clock or half-way closed,,, i backed the sizing die out till i got free handle drop...

I checked every other case as i kept sizing to make sure they would still fit into the chamber with zero resistance...

Again,,, only issue is that 2/3's of the neck is sized... I'll feel what the neck tension is like when I seat the bullets in them,,, if i dont think that they will stay put,,, I'll track down the RCBS neck dies to do Centric run out test...

I'm running reduced loads from 2880 ft-per seconds to 2740 for the 140gr bullets,,, these 6.5 A-Square cases aren't streching at all...

Im sure I'll get 3 to 5 neck sizes for every FL bump when its needed... Will test the partial FL first...

My shooting partner won't let me shoot cartridges that feel tight going in,,, Ha...

We fear that they become flyers...

I had 1 to 1 1/2" moa groups on my last outing,,, hope i can cut that in half on my next trip to the range...

 

[Beluebow]

Po Ackley believed it and proved that by compressing the parent case .004 to .006 while fire forming produced the best results forming the cases and the accuracy was better at this stage of firing. The end results after complete case prep is concentric cases if the chamber is concentric. The best fire formed case will always out perform the fire forming load but this process is a way to utilize the parent loading with good usable accuracy to avoid wasting components just to fire form cases.

J E CUSTOM

We aren't debating the best way to create a Improved cartridge...."The best fire formed case will always out perform the fire forming load"...and yet you said.."during fire forming and producing accuracy that many times exceeds the accuracy of a cartridge that Is full sized for a standard chamber and has "Slop In the chamber fit"...me thinks you are adding your own twist to PO Ackley's words.


"I have heard the stories of how many experts full size and have shot against many state and national champions and learned at an early age not to believe anything they said because most are not willing to tell you the truth how they do everything because they want to keep their status
and don't want to help their competition to become better than they are."

I personally don't know any State or National champions with this attitude, but that's just me. Most have been nothing but accommodating and helpful. We can all learn from someone, even if it's what not to do.

 

[J E Custom]

We aren't debating the best way to create a Improved cartridge...."The best fire formed case will always out perform the fire forming load"...and yet you said.."during fire forming and producing accuracy that many times exceeds the accuracy of a cartridge that Is full sized for a standard chamber and has "Slop In the chamber fit"...me thinks you are adding your own twist to PO Ackley's words.


What I was trying to say was ,If fire forming is done the way PO Ackley recommends accuracy can be very good during this stage. I have built many AI's and have found that Many will shoot 1/2 MOA while fire-forming. I have also built several of the "New" AI's that have factory loading's that are different that the Old method by .014 to .018 and with the new ammo they were not as accurate while fire forming.

Having done Many improved chambers Including wildcats that have had much more increases in powder capacity than the AI's I have found that having a tight bolt while fire forming always produces better accuracy even if it is accomplished with some other method.

It would be easier for me just to agree with some others rather than disagree and just keep my experiences to my self. So we will agree to disagree.

J E CUSTOM

 

[Beluebow]

"It would be easier for me just to agree with some others rather than disagree and just keep my experiences to my self. So we will agree to disagree."

Fair enough.....If it works for you, at the end of the day that is all that matters! Lots of different ways to skin a cat.

 

[BoomFlop]

I have great respect for J E Custom, and believe everything he says. I'm not sure this was the perfect video to prove his point however. For one, the setting (I know it's a stereotype) and his lack of attention to detail, etc cause me to question it more that anything.

Jerry, can you please describe the best way to size my brass (with as much detail as you are willing to take the time for)? I have full length Redding Dies (expanders removed), Sinclair Mandrels and Redding Comp Shell holders.

Thanks for all you contribute to this awesome forum Sir!

Steve

 

[greenejc]

Very interesting. When fitting the case to the chamber with the bolt, does the firing pin need to pulled out so you are not feeling the spring tension of the firing pin?

I was taught to pull the firing pin out of the bolt so I can feel no resistance when closing the bolt.

Jason

Well, since all bolt guns, pump guns and most semi-autos fire from closed bolts, you were taught wrong. When the bolt on a rifle is cycled, it is cocked-either on opening or closing. This pulls the firing pin back inside the bolt face and the firing pin doesn't touch the casing. The only weapons that allow the firing pin to protrude from the bolt face and contact the cartridge's primer on closing are weapons which fire from an open bolt and have fixed firing pins. And not all weapons that fire from open bolts have fixed firing pins, since those that fire high power cartridges need time for the bolt lugs to go into battery, which a fixed firing pin wouldn't allow. Examples of an open bolt gun are the H&K MP5, the M3 Cal. .45Acp, and the Uzi 9mm. They are blowback or delayed blowback actions and the M3 has a fixed firing pin. The M60 machine gun and the M240/M249 fire from open bolts, but the firing pin isn't fixed because the bolt has to have a fraction of a second to rotate closed in the action, so the firing pin is delayed slightly in contacting the primer.

 

[greenejc]

This Video does a good job of explaining proper case sizing The way I prefer to size and the reason I think it is more consistent. I realize that many will not agree with it but it has worked for me and proven to be more consistent/accurate for my bolt action rifles.

As many know I do as little sizing as possible to get the best chamber fit and the best bullet alignment without jamming the bullet in the lands and reducing velocity. If other methods work for you stay with them and be happy with the results. If not happy with accuracy you may find this method very helpful.



Just the way I prefer to size cases for loading accurate ammo.

J E CUSTOM

I've been doing that for years. I use a full length die and size the neck down to just above the shoulder then I chamber the sized casing in the rifle. Since I have multiple rifles in most of my calibers, I will check fit in more than one rifle. If it is just a little tight, its good. All my -06's have very little variation, so if its tight in one it seems to be about the same in the other. I have the same condition with my 300's. If its a medium crush fit in the tightest chamber for a caliber, it is a light crush fit in the others. I get less than 1" groups with all of the rifles that way, and that's good enough for most of my shooting with standard hunting weight barrels. One of these days, I'll re-barrel a Ruger -06 with a 25 or 26 inch heavy Sporter or light varmint contour barrel in 30-06 Ackley Improved just to see what that will do, but for now, I'm pretty happy with the results from my sporters. I do have one Mauser with a 20 inch bull barrel in -06, and it shoots groups of 0.5 inch or less (5 shots) at 100 yards, but it weighs about 12 pounds. I haven't shot it much lately, since it has a couple of issues, but I have a gunsmith who's going to correct those this summer. By the way, JE Custom, thanks for the video.