• LAST CHANCE! Quick Shot Challenge: Caption This Sniper Fail Meme

    Drop your caption in the replies for the chance to win a free shirt!

    Join the contest

6.5 Creed

Reloader77724

Private
Minuteman
Dec 27, 2018
30
8
43
Jasper, Al
I know every rifle is somewhat different. However, I figured that this could be close. So, my question is. What is the OAL of a 140 ELD Match in a 6.5 creed to the lands? 2.87” from tip to base of case is touching for sure. 2.835” does not touch. Factory is 2.81” +/-.
 
Any measurement that we give you would be from a measurement taken using a comparator, which you said was inconsistent, so I’m not sure any of us can answer your question. Maybe ask your reliable gunmakers and precision hand loader friends?? How do they measure distance to lands without using a comparator?
 
  • Like
Reactions: PAYDIRT
I’ve heard from reliable gunmakers and veteran precision hand loaders that the comparator is inconsistent. I just measured my chamber/lands. 2.855” does not tounch but 2.860” does lightly touch lands.

Comparators aren't terribly reliable when you compare them to...other comparators. They are pretty reliable when you use the same one as a frame of reference for your rifle.

Here's the deal, anybody here could give you a reading, but it won't mean much; you don't know the reamer they used, you don't know the headspace of the 'fired case' they're using, and you don't know the round count on the gun.

All of those things matter as it pertains to getting an OAL with a comparator. If I had a 140 ELDM lying around I'd give you one, and I expect it would be +/- .030 in accuracy...which is to say, it'd do you no good.
 
Any measurement that we give you would be from a measurement taken using a comparator, which you said was inconsistent, so I’m not sure any of us can answer your question. Maybe ask your reliable gunmakers and precision hand loader friends?? How do they measure distance to lands without using a comparator?
Sorry I wasn’t clear in my question. I’m curious as to what the avg OAL is between RPR 6.5 creeds and the CAOL of that round.
 
Any measurement that we give you would be from a measurement taken using a comparator, which you said was inconsistent, so I’m not sure any of us can answer your question. Maybe ask your reliable gunmakers and precision hand loader friends?? How do they measure distance to lands without using a comparator?
Sorry I wasn’t clear in my question. I’m curious as to what the avg OAL is between RPR 6.5 creeds and the CAOL of that round.
 
Here is the CBTO and the COAL of the 140 ELD-M.
 

Attachments

  • C0D3AB9D-7431-4E5C-9EC2-CB45999D1028.jpeg
    C0D3AB9D-7431-4E5C-9EC2-CB45999D1028.jpeg
    694.5 KB · Views: 58
  • 096209FB-921F-48E1-97FE-2E9788965751.jpeg
    096209FB-921F-48E1-97FE-2E9788965751.jpeg
    428 KB · Views: 47
  • Like
Reactions: Reloader77724
Like you said, every rifle is different, even between various RPR's. Heres a way to measure you COL without a comparator, if you don't wanna use one. It's worked well for me through the years, though a comparator is a lot easier.
 
IMO - I believe the method above to find the landes and then measuring the base-to-ogive with a (Hornady) comparator lends itself to a higher level of consistency (or accuracy???). When using just the (Hornady) comparator you push the special cartridge case until the special cartridge case shoulder is stopped by the chamber's shoulder. There probably is a small space between the base of the special cartridge case and where the bolt face would have been, resulting in a shorter measurement (.0005-.002). Turning a fired case into a special cartridge case for a comparator may improve (?) the accuracy of the measurement but springback of the brass still introduces a degree of inaccuracy because of measurements impacted (?) by the shoulder locations. If I competed or did ELR shooting/hunting I would use the first method I mentioned.

However, how long before erosion of the landes changes the measurement and the behavior of the rifle in question? And of course, no two rifles are alike.

Cartridge components, i.e., cases, bullets, powder, grains, etc., and measurements, similar to the info in reloading books, should be considered a basis fo begin your experimentation. Nothing more.

That said, I truly appreciate the expertise and practical experience shared by forum contributors. It often reminds me of how much I don't know.
 
  • Like
Reactions: Reloader77724
Not all cases, or in this case modified cases, have the same dimension from base to shoulder datum line, and not all bullets, even from the same lot, have the same base to ogive dimension either. Not all comparators are going to measure the ogive at the same spot on the bullets as well. So when you take the reading with a specific modified case, bullet, comparator, and barrel, it’s a measurement that is unique to what you used to measure it with.
 
Stoney Point makes one or at least use to. I can not speak personally on it but many others like it. It also comes at a much higher price, which is why I purchased the Hornady oal gauge instead.

Personally, I use a fire formed case that has been shot in my rifle. I take the average of ten measurements. Is it spot on, probably not but very close. As others have said there are a lot of parts in play such as spring back etc. that may prevent your measurement from being exactly accurate. But it gets me close and then I play with seating depths and watch for pressure signs.
 
  • Like
Reactions: garandman
Stoney Point makes one or at least use to. I can not speak personally on it but many others like it. It also comes at a much higher price, which is why I purchased the Hornady oal gauge instead.

Personally, I use a fire formed case that has been shot in my rifle. I take the average of ten measurements. Is it spot on, probably not but very close. As others have said there are a lot of parts in play such as spring back etc. that may prevent your measurement from being exactly accurate. But it gets me close and then I play with seating depths and watch for pressure signs.

I think Hornady bought out or otherwise took over making them.
 
Just measured my Rem 700 action / Southern Precision bbl in 6.5 CM w/ Hornady Comparator. The 6 measurements were:


2.2630
2.2630
2.2615
2.2635
2.2645
2.2635

Varied 0.003. I suspect its not really gonna make much of an accuracy difference if I settle on 2.263.
 
Just measured my Rem 700 action / Southern Precision bbl in 6.5 CM w/ Hornady Comparator. The 6 measurements were:


2.2630
2.2630
2.2615
2.2635
2.2645
2.2635

Varied 0.003. I suspect its not really gonna make much of an accuracy difference if I settle on 2.263.

If it were me, I'd probably start it at 2.263 and work back in .005 or .010 increments to test seating depth. You'll find an area where it shoots much better than others. You can then move in smaller increments once you've found a rough 'ideal seating depth'.

You wouldn't want to just call it good at 2.263, because there's a 99% chance it will shoot better at another depth.
 
If it were me, I'd probably start it at 2.263 and work back in .005 or .010 increments to test seating depth. You'll find an area where it shoots much better than others. You can then move in smaller increments once you've found a rough 'ideal seating depth'.

You wouldn't want to just call it good at 2.263, because there's a 99% chance it will shoot better at another depth.


2.263 is the length to ogive just touching the lands.

Im at 15 off right now and grouping right at 0.50 MoA.

Got some rounds at 50 off to test next.

The 2.263 is just the length to begin calculating the "jump"
 
I have a jag that is cut flat on the face (no tip). I slide that jag on a rod down the bore on a closed bolt and put a ring of tape on the muzzle end. Then use a bullet (usually with a case behind it just so I can touch/move the bullet) and can push back and forth between the case and the rod to find where the bullet just touches the rifling, then ring another piece of tape around the rod on the muzzle.

Measure from tape ring to tape ring. That gives COAL for THAT bullet to touch lands. Seat to that COAL and measure ogive for head-to-ogive dimension. Method is probably +/- .005ish. I usually subtract .025 from my COAL and run with it.