Ogive

[jfkephart]

I am new to reloading. I have a custom rem 700 action in 6.5 CM. I have been using factory ammunition up until recently when I decided to start reloading. Admittedly using Hornady 143 ELD-X factory ammunition I found it difficult to close the bolt. I didn’t give it much thought until I went to measure the ogive. When I do this I find my OAL to be .010 of the lands is way short. What should be 2.800 by specs is 2.650 based on my measurements. When I went back to some left over factory ammo I chamber a round and on closer inspection find spiral markings etched into the bullet. I assume by this I am jamming the round pretty for down the chamber especially considering the difficult bolt close.

Is there a potential problem with the rifle? I have go no go gauges on order to check the chamber. Otherwise, if I use the ogive measurements I will be seating my 140 ELD-M bullets I intend to use reloading really far down into the case which I am concerned will cause case volume problems. Any help to put me on the right path is very much appreciated. Please if you respond assume I know nothing which is pretty close to the truth.

Thanks

 

[pirate ammo]

move your thread to the reloading forum on here , and you will get more answers then head can stand,,

 

[243winxb]

Looking at SAAMI standards may help.https://saami.org/technical-information/cartridge-chamber-drawings/

The go no go gauges dont measure the throat/leade.

Member at gun club had same problem with Hornady factory ammo in a Savage 6.5

 

[jfkephart]

“Looking at SAAMI standards may help.https://saami.org/technical-information/cartridge-chamber-drawings/

The go no go gauges dont measure the throat/leade.

Member at gun club had same problem with Hornady factory ammo in a Savage 6.5”

So would this indicate the throat/leade was cut short? Or this this typical for a custom rifle with a match chamber? I only ask because while I’ve been shooting for a really long time I’ve never really bothered to investigate the inner workings of a rifle at this level. I’m used to factory rifles with sloppy tolerances.

BTW, the SAAMI spec was helpful, thx.

Looking at SAAMI standards may help.https://saami.org/technical-information/cartridge-chamber-drawings/

The go no go gauges dont measure the throat/leade.

Member at gun club had same problem with Hornady factory ammo in a Savage 6.5

 

[243winxb]

custom rem 700 action in 6.5 CM.

So would this indicate the throat/leade was cut short? Or this this typical for a custom rifle with a match chamber?

A custom rifle may have a different leade/throat, shorter then SAAMI standards. Its ok for the most part.

When seating a bullet, the bullet ogive should not go below the case mouth.

Your measurement look like COL. Google "bullet ogive"

 

[sidecutter]

wheeleraccuracy | Videos

 

[JMayo]

I think something like a vld wouldn't jam so bad.

 

[rammac]

You're confusing Overall length and length from base to ogive.

Cartridge Overall length (COL) is what is specified in the manual (cartridge base to bullet tip) and it is 2.800"
When you measure from the base to the ogive it will be quite a bit shorter.

 

[rammac]

If you are trying to seat the bullet with the base to ogive length being 2.800" then the bullet will be way too far forward and yes, it will jam at least .010" - .020" in to the lands.

 

[Texas10]

How and when are you trimming your brass and how much are you setting shoulders back? You could have more than one issue affecting bolt closure.

 

[pirate ammo]

told you, stick around here and your head will EXPLODE, but it's a good thing. People here KNOW what their talking about.Stay around, you will learn grasshopper.

 

[dickn52]

Book. Lyman 50th is current issue. And yes this stuff can be very technical, and rightfully so. Remember you are creating controlled 'mini bombs' and sticking your nose on top of them. Pirate ammo said it best. 100 members will have 101 different ways to do stuff...but they/we all end up at the same end point we hope.

 

[DirtySteve]

All the reloading manuals show the COAL (Cartridge Over All Length) not base to ogive. so you are cramming the bullets into the lands. Which will increase your chamber pressures. So take a step back and take a good look at what you are doing. We don't need any bad accidents this time of year or any other for that matter.

Merry Christmas to All!

 

[josebd]

Factory barrel?

 

[dickn52]

By book I meant understanding the design of bullets. I use an OAL gauge on each bullet.

 

[Laurie]

It may be inadequate freebore as suggested in previous posts, but with it being 6.5 Creedmoor I suspect a more likely explanation is inadequate chamber to bullet clearance in the leade - ie the bullet's O/D is marginally greater than the leade's internal diameter. The stated inside diameter on PT&G's drawing (and I presume the SAAMI chamber specs, but I've never checked this) is 0.2645", ie a mere half thou' greater than nominal bullet diameter. I've measured many makes/models of current 6.5mm bullet and most are 0.2640" or even marginally above on the shank, one model I measured actually exceeded 0.2645".

So, the reamer only needs to be a tiny amount undersize and you have a clearance problem that shows up as resistance to chambering and rapid leade erosion. I've suffered this with two Creedmoors I used in the past, one custom the chamber cut with a very early reamer; the other a Savage 12 LRP model. I did a search on the 6.5 Creedmoor forum for this issue and it is by no means a rare problem, early Savages allegedly particularly prone to it.

This condition makes the rifle very bullet sensitive. The Savage LRP I tried shot brilliantly with 140gn Nosler CCs which also chambered easily, but the larger diameter 139 Lapua Scenar which is usually a design that works in every 6.5 irrespective of cartridge or make of barrel, was uncharacteristically hopeless.

As well as feeling resistance on chambering, a bulleted round that is chambered and then ejected will show lands marks along all of the bullet shank ahead of the case-mouth, or if it is a marginal clearance issue part of the shank or maybe one side only. A correctly dimensioned reamer apparently barely removes the lands from the blank and an undersize one leaves vestigial lands in place! I first became of the issue before I got as far as loading and shooting any ammo as measuring COALs for a range of some half dozen bullets from Sierra, Berger, and Nosler using the Hornady OAL gauge produced resistance to pushing the rod forwards for some models before the bullet ogive got to the throat and my initial readings were hopelessly short. (Putting more pressure on the tool's rod eased tighter bullets fully forward through the tight section into the lands and producing OAL values in the expected range.)

 

[AJC]

At this point the cheapest and easiest way to figure this out is to use the "Stony Point/hornady" Oal gauge and see what is going on for sure with a few different bullets. If your having issues with more than three different manufacturers bullets not measuring near expected values then you know a trip to the gunsmith is warranted. Real data is how any problem should be addressed. Get a tool that gives you data points and work forward from there.

 

[jr600yd]

Good advice above. Also size one of your cases and trim to length. Try to chamber it. If you feel resistance you have a sizing issue. Reset your sizing die. If no resistance try the next step. Make a dummy round. Sized case, no primer or powder. Seat a bullet. Record the base too ogive measurement, chamber the dummy round and measure it again. Resistance? Marks on the bullet shank? Seat bullet minimum.010 deeper in the case and try again. Repeat till closing the bolt with no resistance.

Also try the Wheeler method mentioned above. It will tell you your BTO measurement.

 

[Jet]

There are a few forum members who live in the Medford area. @Gina1 is one of them and she might be able to give you some advice. Having a mentor getting you started makes life a lot easier.

Good Shooting

Rich

 

[INTJ]

jfkephart,

I live in Springfield and usually make the 600 and 1000 yd BR matches at Camp White (RVSSA). Send me a PM and we can discuss over the phone if you like.

Blaine