Seeking advice - 6.5 prc reloading

[Nine Banger]

Finally was able to hit the range again with some properly sized brass and a chrono. Worked up from 55 grains to 60.
55 - 2755 easy extraction.
56 - 2838 easy extraction.
57 - 2914 easy extraction.
58 - 2972 easy extraction.
59 - 3078 little bit of bolt lift, extractor mark.
60 - 3120 stiff bolt, ejector mark.
Factory 147 eldm - 2780 avg for 3 rounds.

My plan is to load 20 or so at 58.5 and see how they do in a group and verify at 600.

I feel this barrel may be a little slow, or H100 is not the best powder for speed. All the tmk rounds shot in a single group were again under 1.5 moa with a fist for a rear rest. So H1000 seems to be an accurate choice, and thats really what matters.

Thanks to all who chimed in here, every day a little wiser!

57 is the safe bet for hunting (function) and travelling (heat).

 

[J.B.]

57 is the safe bet for hunting (function) and travelling (heat).

Gotcha, thanks. Im going to challenge you, but these are genuine questions and I want to understand why thats your recommendation.

Some additional info that may be a factor is that around 59+ grains, the loads are compressed. Does this change the pressure curve?
Im using factory Hornady brass, would premium brass change pressure signs as well?

Why 57 and not 58, when I didnt see any high pressure signs until 59 grains? In hindsight, 58.5 may be a little too close to pressure to be a good choice. Shooting conditions during the test were cool, but a good average of my hunting conditions.

I don't want to push safety limits, but would be nice to have slightly better performance than “spicey creedmoor” out of a prc lol.

 

[wind gypsy]

Step 1, figure out how far you're bumping shoulders.

 

[sacox31s]

Buy lapua or adg brass then you’ll be able to load higher charge weights. Hornady brass is too soft to reload at higher pressures.

 

[mtnbound]

Gotcha, thanks. Im going to challenge you, but these are genuine questions and I want to understand why thats your recommendation.

Some additional info that may be a factor is that around 59+ grains, the loads are compressed. Does this change the pressure curve?
Im using factory Hornady brass, would premium brass change pressure signs as well?

Why 57 and not 58, when I didnt see any high pressure signs until 59 grains? In hindsight, 58.5 may be a little too close to pressure to be a good choice. Shooting conditions during the test were cool, but a good average of my hunting conditions.

I don't want to push safety limits, but would be nice to have slightly better performance than “spicey creedmoor” out of a prc lol.

I would load 58gr and see how they group.

Compressing powder too much can affect the burn rate as the compression of the bullet against the powder is damaging or changing the shape of the powder.

 

[J.B.]

Buy lapua or adg brass then you’ll be able to load higher charge weights. Hornady brass is too soft to reload at higher pressures.

I had a hunch that was a possibility. Simply put, harder brass expands less for a given charge and so can handle more pressure?

 

[J.B.]

I would load 58gr and see how they group.

Compressing powder too much can affect the burn rate as the compression of the bullet against the powder is damaging or changing the shape of the powder.

Thanks for the reply. So far the gun has grouped well with everything I've put through it, just need to settle on a load and shoot a group to confirm.

 

[jesco88]

Step 1, figure out how far you're bumping shoulders.

I was about to mention this, but I will emphasize this point again. The first step you should do here is get a headspace comparator gauge. Hornady makes a decent one for like $45. You have to know how far you're bumping the shoulder.

 

[wind gypsy]

I was about to mention this, but I will emphasize this point again. The first step you should do here is get a headspace comparator gauge. Hornady makes a decent one for like $45. You have to know how far you're bumping the shoulder.

An empty pistol case or any cylinder with squarely cut ends with the right internal diameter dimension can work in a pinch too.

 

[jesco88]

An empty pistol case or any cylinder with squarely cut ends with the right internal diameter dimension can work in a pinch too.

That's a good idea. Reminds me of the old pistol casing for ear pro trick. (Not recommended... but its better than nothing)

 

[J.B.]

Step 1, figure out how far you're bumping shoulders.

I was about to mention this, but I will emphasize this point again. The first step you should do here is get a headspace comparator gauge. Hornady makes a decent one for like $45. You have to know how far you're bumping the shoulder.

Is this in reference to my initial tight chambering issues? I was not sizing properly, but have since sorted that out.

Or can bumping the shoulder too far create pressure issues?

 

[sacox31s]

I had a hunch that was a possibility. Simply put, harder brass expands less for a given charge and so can handle more pressure?

Yes, all things being equal, you'll be able to get higher velocities/pressure with harder stronger case heads in brass like Lapua or ADG.

 

[jesco88]

Is this in reference to my initial tight chambering issues? I was not sizing properly, but have since sorted that out.

Or can bumping the shoulder too far create pressure issues?

Most bottleneck cartridges headspace from the bolt face of the case to a datum point on the shoulder. (except for belted magnums and rimmed cartridges). By comparing the distance between the bolt face and a consistent datum point on a fired casing against a resized case, you know how much you're bumping that shoulder down. You want 0.002"- 0.003" shorter than a fired casing. This way- you're not overly reducing case life and accuracy potential by pushing the shoulder too far down. I suppose if you're near max load and you're sizing the casing too much, you are technically reducing your case capacity. This would increase pressure. Although, I don't know really how much case capacity you're losing this way... so I can't speak intelligently about that.

For me- the most important reason for knowing how much you're bumping the shoulder is ensuring that you have enough clearance/room, whatever you want to call it... for that casing to get into your chamber when its dirty or etc. If you're resizing your brass and not moving the shoulder at all... all it takes is a spec of dirt and your bolt isn't closing, or it isn't closing easily.

 

[wind gypsy]

Is this in reference to my initial tight chambering issues? I was not sizing properly, but have since sorted that out.

Or can bumping the shoulder too far create pressure issues?

You dont know how much you're sizing your brass, to me that is a reloading basic worth understanding. If you're oversizing you might have less reliable ignition and poor case life.