Need advice from expierenced reloader....270 cal OAl problem

[Bmac1949]

I'm working on loading .270 winchester for a Remington 700 and this is my first attempt loading .270 ammo and am having a problem with getting the AOL to come out right. Cases are trimmed to 2.530" this is the lyman trim to length and I am seating Hornady 130GR SP .277 cal Interlock bullets. I made up a couple of dummy rounds and they are measuring 3.234" before I have even seated it to the canalure and this is below minimun OAL for Accurate 2700 and IMR 4227 which is the powders I'll be using. I pulled the bullet out of a 130gn Winchester Power Point factory round for comparison and found the length of the bullets to be similar but the canalure on the Winchester bullet is much further back than the Hornady by atleast a quarter of an inch. So this is causing my rounds to fall below minimun AOL recommendations. Any sound advice will be greatly appreciated. By the way I'm new to the forum and am looking forward to meeting fellow reloading enthusiast.
Thanks

 

[Blackrock]

You can bring it down to 3.210 with no problems. You don't mention the powder charge weight you are starting at? And what is your COAL with the bullet seated to the cannelure?
Bullets with a cannelure that will fit many different cartridges don't always wind up with a seating depth that puts the cannelure right at the case mouth anyway.

 

[MEHavey]

My experience is that seating to Hornady's cannelures results in a somewhat shorter OAL round than might be seen in "generic" reloading manuals. (Loads in the Hornady Manual, however, are set to this shorter/cannelure cartridge length.)

Hornady's (6th ed) recommended OAL for their 130 SP (#2730) is 3.210
Hornady does not list either AA2700 or IMR4227 powders for this bullet.

QuickLoad lists the 270Win as a 65,000 psi cartridge (in a strong bolt action), and some of Hornady's loads for that bullet/OAL combination (EX: RL-19/59.4gr or RL-22/61.3gr)) get up there in pressure. I'm not so sanguine and would not load to those pressures.

Shaving 10% off that 65,000psi max, leaves me 58,500psi as tops. With that in mind, Quickload predictions for a 24" 270Win/HNDY130SP/OAL=3.210@cannelure are:

AA2700:
- MAX 53.5gr/2,900fps/58,300psi
--- NOTE: Sierra Starts at 47.7gr and Tops out at 51.7 for a longer OAL of 3.300"



**************************************************
IMR4227 is too fast a powder for the 270Win. DO NOT USE
**************************************************

 

[243winxb]

Do not use this powders for a 270 Win rifle.> Edit*

IMR 4227

Seating Depth, read this > http://www.brownells.com/.aspx/lid=12897/GunTechdetail/Gauging_Success___Minimum_Headspace_and_Maximum_COL For loading data, go here > http://data.hodgdon.com/main_menu.asp

 

[steve4102]

OAL is not manual specific it is rifle specific. The OALs listed in manuals are there only to tell you what they loaded to, it is not a required Min or Max. Hell some manuals don't even list an OAL it's that unimportant to the handloader. Here is what Western Powders says about OAL.

SPECIAL NOTE ON CARTRIDGE OVERALL LENGTH “COL”
It is important to note that the SAAMI “COL” values are for the firearms and ammunition manufacturers industry and must
be seen as a guideline only.
The individual reloader is free to adjust this dimension to suit their particular firearm-component-weapon combination.This parameter is determined by various dimensions such as 1) magazine length (space), 2) freebore-lead dimensions of
the barrel, 3) ogive or profile of the projectile and 4) position of cannelure or crimp groove.

So seat them to what ever works for you. If you want to seat to the cannelure, go for it. Just start low and work up like always.

BTW Hornady #7 list the OAL of that bullet at 3.210.

Are you sure about IMR 4227??? This is a fast powder and I can't find any tested data for it.

 

[MEHavey]

Are you sure about IMR 4227???

See post #3 above. You are correct. It is waaaaaay too fast.
It will hit 60,000psi with only 37gr (3/4 of the case filled).

DO NOT USE IMR4227

 

[MEHavey]

Better powders for this cartridge/bullet combo are:

N560
RL22
IMR7828 SSC
RL19
Any of the 4350s (probably best)
IMR4831 (also probably best)

Another Note: the 270, like the 30-06, has been historically offered in lever action rifles. This limits commercial ammunition loadings.
Owners of strong/bolt action rifles need to be handloaders to get the best performance out of these two cartridges

 

[Bmac1949]

COAL of the dummy round is 2.691" with the bullet seated at the bottom of the canalure and it looks like I'll be ok with the 3.210" OAL. Both Lyman and Lee give a longer OAL for the 130gn jacketed bullet. Lyman 3.250" for all powders for this bullet and Lee list 3.330" OAL for AA2700 and 3.250" OAL for IMR 4227. I use the recommended start grains and will increase in one grain increments staying 1% below the listed max. AA2700 max load of 52gr reaches a pressure of 52,000 CUP and IMR 4227 recommends a max load of 30.0gr at a pressure of 51200 CUP. Now I'm trying to figure out how CUP relates to PSI. I found a conversion equation PSI=CUPX1.498-17148 so that should give me a max pressure of 60748 PSI and 59550 PSI respectively. Thanks for the help and good advice.

 

[Bmac1949]

I'll stay away from the IMR 4227. LEE lists it but at that pressure I don't want to mess with it. I'm going to take slow as this is a much hotter round than the .30-30 Winchester that I started with. Thanks

 

[Grumulkin]

Consider IMR 8208 XBR.

 

[68wj]

Unless you feel the need to put a crimp on your cartridge, just ignore the cannelure. Ideally you will want to find the OAL that works best in your rifle by finding how far out your bullet meets the lands and then backing off from there. This can be accomplished many ways, from precise measuring tools to blackening a bullet and loading the cartridge in the chamber and looking for rifling marks.

 

[James2]

IMR4831 (also probably best)

My powder choice too.
Never mind the cannelure. Seat them to the depth you want. Make sure they are short enough to work in your magazine.

 

[MEHavey]

Now I'm trying to figure out how CUP relates to PSI.

It's very messy, particularly since PSI is a (peak) force, and CUP actually wraps "work" into the equation. No one equation relates the two with precision, but this (European-based) one:

PSI = -2806.88 + 1.20911*CUP

...gets pretty close as well.

One of the better outlines of the problem is here...
http://www.shootingsoftware.com/ftp/psicuparticle2.pdf
...in which there is an actual 1-to-1 comparison chart tied to individual cartridges

I find that if I AVERAGE the two equations:

PSI =((-17902 + 1.516 *CUP)+(-2806.88 + 1.20911*CUP))/2

... it gets very interesting, but still no exact match.

 

[243winxb]

Imr 4227

The old IMR/Dupont free powder guide from the company has always listed all there powders under 270,30-06 type cartridges. This is where Lee got the data i would guess. IMR 4227 is a fast burning rate of powder, to fast for a large capacity case. When working up a load, pressure would go up fast with just an increase of 1/2 of a grain of powder. Current free powder guides offered from Hodgdon will not list IMR 4227 as its not a good choice of power for the 270 win. and many other large capacity cartridges.

 

[Bmac1949]

I got my test rounds made up today for the .270. Used AA 2700. Started with 49.4gr(minimum load) and worked up in half grain increments to 51.5gr. 52gr is max load. I decided to stay from max load that was approaching 60,000 PSI. I did have a small problem with crimping. A couple of shells came out of the seating die with the shoulders pushed back a bit. I could have had the die too far in but I reset the die and the same thing happend. So I ended up not crimping and will feed one shell at a time and work out the crimping bug when I start loading hunting rounds. These Hornady 130gr sp Interlock seat so far back at the canalure that I'm wondering if the ogive being so far back from the lands will hurt accuracy? The advice I got in this thread was very helpful ie. staying away from the fast burning powders for these types of cartridges.

 

[MEHavey]

I strongly recommend that you back the seating die off the case by a half turn and forget crimping completely on your 270.

For one thing, consistant crimping is highly dependent on every case being exactly the same length. If not, crimping is overly-heavy on some cases, and light-to-non-existant on others. That does nothing for accuracy and--like you found--sometimes distorts the case.

For another, you don't have enough recoil in the 270 to require crimping to prevent bullet setback in the magazine. So go ahead and load them into the magazine uncrimped. (You can fire a couple of rounds and then unload the magazine to check OALs on the remaining cartridges to set your mind at ease on this one.)

And third, normal neck tension alone is enough to securely/consistantly lock the bullet to the case -- and results in the most consistant bullet release upon ignition.

Try it. You'll like it.

~~~~~~~~~~~~~~~~~~~~

As to seating depth, remember also that you do not have to seat to the cannelure. If you've tested/know what maximum cartridge length will just hit the lands, back off the width of ordinary paper clip wire (which is 30 thousands) and go from there if it still fits in the magazine. If not, seat to magazine length.

REMEMBER: That OAL is for that bullet only. Other bullets/other designs will engage the lands at different OALs. So if you change bullets, test for max OAL again and change your seating depth to accomodate that fact.

 

[Bmac1949]

I'm not too worried about the crimp and once I find out what load works best for me I'll start moving the bullet towards the lands. Headed out in the AM to the range to see how my test rounds work out.

 

[MEHavey]

Roger. Good luck.

 

[Bmac1949]

I fired the test rounds for my .270. Had mixed results the two smallest loads, 49.4gr and 40.5 grains or AA 2700, were either off the target or the group size was unacceptable. The heaver loads(51.0gr and 51.5gr) grouped at > 2" at 100 yds. I'm going to load another set of test rounds of these loads and see if I get the same results. I'm also looking at other powders that have been suggested in this I definitely want to have this rifle shooting sub 1 minute MOA groups. I wish these test rounds had been as definitive as the .30-30 rounds that I tested. There was no question as to which load was the more accurate and with a little more tweaking to find the right COAL for my rifle it shot a .75" group at 100 yards. Once I find the right combination for the 270 I expect it to do better. I can see now that the journey to find that "perfect" load has a lot of twists and turns...makes it fun and challenging. Later