Project 7 LR

[Shadow292]

My LR 7mm

 

[Shadow292]

it looks like it might be propagating from the neck junction. stick a piece of brass down there and post another pic with the Teslong.
If the chamber has an abnormally long neck maybe the extra freebore is causing the carbon to build up. you might have to let your brass grow a fair amount to seal the chamber better. which is gonna be a PITA if you can only fire 20 rounds at a time.

I wish I could see a picture of the brass in there with the carbon build up.

 

[Shadow292]

First two are duplicates
Virgin unfired untrimmed Norma case without mirror
2.495
Next is same case with mirror in battery
3rd is my fired trimmed case in battery 2.490

 

[Shadow292]

Looks like I should have bought the bore scope and checked this before I did anything to my cases.
I definitely see what your saying. Damit. Lol
Always leaning things the hard way

 

[DJ Fergus]

@Taylorbok Do you think the distance from the neck of the case to the neck junction of the chamber in those pictures is enough to possibly cause his carbon ring in the throat? I'm just asking cause it's possible that may have caused my carbon issues also.

 

[Shadow292]

I still have 20 brand new cases.
I'm going to load 5 over and over several times and monitor this gap. If the issue fades away as the neck stretches out closing that gap I'll be golden.
My 140 fire formed cases will be junk but that's still better than starting from scratch with new powders.
I should have some results in a couple weeks

 

[bengineer]

Try running those fireformed cases through a complete FL sizing die a few times. You may be surprised how much a case neck grows being dragged across the expander ball a few times.

 

[Shadow292]

They been fired and trimmed 5 times now.
Not much brass left to stretch that much

 

[Taylorbok]

That is more neck room than I'd like to see. I'd say about half or 1/4 of what you are showing would be ideal. Let some brass grow if you can. Sinclair makes a chamber length gauge that you can use to measure this but if you just keep an eye on it with the bore scope and don't let them get to long.
see if it helps your carbon issue. I don't have any experience with Magpro powder but it's in the ballpark of powder you should be running.

If closing up that gap solves your issue I would just chuck your brass and start with new and let it grow, IMO it wouldn't be worth losing the barrel life trying to grow the brass you have 7 rem mag brass can be had relatively cheap if you can find it.

I will try and post some pics tonight or tomorrow of a couple chambers I have for you to compare.

 

[Shadow292]

That's exactly what I'm going to do.
I sure appreciate you chiming in with this even if it doesnt solve my carbon issue I'd never thought to check this. I can see it causing accuracy issues as well so I'm definitely glad to have discovered it.
Learning is expensive
140 cases fired 5X = alot of wasted bullets and powder.
Plus now I have to do it all again.
My advice to anyone wanting to reload is buy a bore scope before you even buy or build a rifle. You'll thank yourself later

 

[Taylorbok]

That's exactly what I'm going to do.
I sure appreciate you chiming in with this even if it doesnt solve my carbon issue I'd never thought to check this. I can see it causing accuracy issues as well so I'm definitely glad to have discovered it.
Learning is expensive
140 cases fired 5X = alot of wasted bullets and powder.
Plus now I have to do it all again.
My advice to anyone wanting to reload is buy a bore scope before you even buy or build a rifle. You'll thank yourself later

No worries, its not something lots of people talk about but can be an issue. Saami trim length isn't always the best option, once you have a piece of brass that fits the chamber well, (about .010" short of that lip). measure it and make that your new trim length. write it in your manual or reloading notes or what ever.

 

[Maol]

That's exactly what I'm going to do.
I sure appreciate you chiming in with this even if it doesnt solve my carbon issue I'd never thought to check this. I can see it causing accuracy issues as well so I'm definitely glad to have discovered it.
Learning is expensive
140 cases fired 5X = alot of wasted bullets and powder.
Plus now I have to do it all again.
My advice to anyone wanting to reload is buy a bore scope before you even buy or build a rifle. You'll thank yourself later

$40.00 best gun related purchase I ever made.

Teslong Rifle Borescope, 36 Inch Flexible Bore Scope Gun Barrel Camera - Fits .20 Caliber & Larger Hunting Shooting Firearms, Gun Cleaning Inspection Camera Works with Android, Mac, Windows: Amazon.com: Industrial & Scientific

Teslong Rifle Borescope, 36 Inch Flexible Bore Scope Gun Barrel Camera - Fits .20 Caliber & Larger Hunting Shooting Firearms, Gun Cleaning Inspection Camera Works with Android, Mac, Windows: Amazon.com: Industrial & Scientific

www.amazon.com

 

[Shadow292]

I dont own a laptop or home computer so I bought the 26in rod style with display for $120 very impressed with the quality price ratio on teslong products

 

[Maol]

I dont own a laptop or home computer so I bought the 26in rod style with display for $120 very impressed with the quality price ratio on teslong products

My 36" Flexible works off Android Phone. I haven't even tried my laptop. The 'Rod' type might be worth it though. Especially with their mirror kit.