Brass trim length

[Frogeye]

Hey folks, newbie here, want to say hi and enjoy your posts.Just built my first 6.5 grendel and need to load up some hunting/shooting rounds. Haven't loaded anything in 30+ years. So here's where I'm at.

Shot 2 boxes of hornady 123 eld match, mainly adjusting gas block and scope. Did no measuring on the fired brass. Deprimed and tumbled and then measured. Cases were 1.524" to 1.534", first thought was this was due to resizing. Was trying to decide what length to trim to. Was able to fire 2 more rounds (at a deer) only found 1 brass. It measured 1.524". I know I need a few more unfired for measurements but off the top of your heads what trim length should I be looking at? I see no reason to go with 1.510" as per my hornady manual. The case lengthening has to be from the chamber, my guess? Thanks for any help, and it's a ar build, 20" bbl.

[mdram]

max is 1.52, trim to is 1.51 per hornady

[Frogeye]

Yes, that's what I saw, I just don't see a need to trim to 1.51. My mind can't justify it if it comes out fired at over 1.52. My thinking is I'll have less case life than if I only trimmed to 1.52. That's why I threw this out there to you guys, yall know more about the grendel and reloading than I do. I just want every round to go bang and go reasonably close to where I want it to go.

[Csitt]

Yes, that's what I saw, I just don't see a need to trim to 1.51. My mind can't justify it if it comes out fired at over 1.52. My thinking is I'll have less case life than if I only trimmed to 1.52. That's why I threw this out there to you guys, yall know more about the grendel and reloading than I do. I just want every round to go bang and go reasonably close to where I want it to go.

I have been reloading since Oct. I have 3 firings on most of my brass and I have only had to trim 2 of the cases. My guess is they were long from Federal since they were 1 firing. I have done measurements before and after firing/resizing. Most movement in brass was only when I was over sizing the brass. I'm using lee dies now. Once I figured this out. I only see about 0.001" of brass movement. I'm not loading them over published loads.

Chuck S.

[Frogeye]

Thanks Chuck, I've measured some unfired, and I "think i remember" they measured 1.514". And I used rcbs dies, not the sb version.

[Frogeye]

What is the general thought as to which are the better dies? Good dies, not the high dollar match type?

[VASCAR2]

[Happy2Shoot]

These are very helpful.

headspace gauge

5523headspace_gauge.e1945272.jpg

Measure a few fired cases, subtract 0.003". That is what you should size your brass to.

[grayfox]

Your barrel seems to have a long throat if you're getting fired cases at 1.524. I had one like that and frankly got rid of it, too much case stretching for me. 'Course I had a few barrels and that one was the longest chamber, so odd man out had to go.

The Saami trim length is as specified in Hornady and elsewhere, 1.510-1.520. That being said if you only have one barrel and you resize/ trim to 0.003-0.004 less than fired length (the shoulder needs to be 0.003-0.004 less than it is as-fired, then OAL trims down to fit), your brass will work in that barrel. I doubt seriously if Federal or any other ammo maker worth their salt would make a round with an out of spec case length --- think of the lawsuits they risk. Most new cases will be sized at or even a bit below saami minimum, 1.509-1.510.

[myrifle]

Forster dies is what ibuse gor my ar grendels much better die then hornady.

Pair it with a Redding micro seater or foster micro seater die and your good to go.

Set it up for a .003 or .004 shoulder bump and trim it down too 1.510 as per specs case length.

But honestly if your cases are coming out that long. I would rehome that barrel or just use it for factory ammo.

[Klem]

Frogeye,

Welcome to the Forum.

Before jumping to conclusions can you give us some more info please.

1. What is the average case length of the factory ammo you are using - out of the box with the bullet still in it, unfired.
2. Can you confirm the case length of that ammo once fired, before you do anything to it.
3. What is the length of the case after you size it (to see if the die you are using changes the length at all).
4. Also, can you please give us the diameter of the neck of a fired case. What is the neck expanding to, to release the bullet?

Might just be long factory cases to start with, so nothing wrong with it.

I prefer Forster dies for this calibre.

I trim at 1.52 back to about 1.515, although this is a forgiving calibre for case creep and trimming. You rarely have to do it.

[Frogeye]

Ok, here goes, thanks to ALL.
Happy, I've got the gauge in my cart, will order it "if I really need it", do I?

Gray fox, I think I agree with you on the long throat. I'm going to ask a lot more questions later about shoulder bumping.

Klem, your answers,
1. COL, 2.251-2.252, brass length, 1.511-1.517
2. I only have one (1) unfired, unsized to measure, 1.524
3. Forty (40) sized, 1.524-1.534
4. Need to add the velcro to forward assist, dinged case necks, again, only 1 available to measure, as best as I could measure with the dinged neck, 0.299 OD, 0.269-0.270 ID.

Once again, Thanks.

[myrifle]

Ok, here goes, thanks to ALL.
Happy, I've got the gauge in my cart, will order it "if I really need it", do I?

Gray fox, I think I agree with you on the long throat. I'm going to ask a lot more questions later about shoulder bumping.

Klem, your answers,
1. COL, 2.251-2.252, brass length, 1.511-1.517
2. I only have one (1) unfired, unsized to measure, 1.524
3. Forty (40) sized, 1.524-1.534
4. Need to add the velcro to forward assist, dinged case necks, again, only 1 available to measure, as best as I could measure with the dinged neck, 0.299 OD, 0.269-0.270 ID.

Once again, Thanks.

If your case necks are hitting the deflector that bad you need to fix the over gas issue instead of putting a bandaid on it.

[Klem]

Frogeye,

Thanks for that info.

The case length on those Hornady 123's is fine. Grendel SAAMI chamber spec for the neck is .300" so your chamber has plenty of clearance to release the bullet without dragging. So, the length the case stretching is unusual. Maybe Hornady crimps them tightly, and/or maybe the brass is soft. When you fire your own reloads you will know whether case stretching on firing is typical for your gun and that brass.

The thickness of brass at the neck sounds about right. Lapua is 0.0135" and yours is the same.

The idea that your sizing die lengthens your brass from 1.524 to 1.534 is without doubt an issue and all down to that die. I am guessing the expander ball is dragging the neck with it on the out-stroke. Is it a Lee die? I use a Forster with the expander ball removed. Only the outside of the die gets touched. The resulting neck is round enough to accept a bullet and the bullet acts as a mandrel when it seats. Accuracy is fine without the expander ball.

Dinging on ejected cases is not unusual in Grendels. You can use Velcro but a better way is to cut the ejector spring shorter by a couple of coils. Velcro mitigates the symptoms but it won't fix the cause. Ejector springs are only worth a couple of dollars and are replaceable, so there is no risk. This has been discussed in the past. I did it to mine and no more dings.

[Frogeye]

Thanks, the ejector spring has an o-ring, before trimming the spring, I'll remove it and see what happens to the necks.

The dies are RCBS. But until I get more fired brass to measure I can't be sure it is the die lengthening the brass, it might be the chamber.