I have received my Model, 70 formerly a 270WSM, now rebarreled to 6.5WSM.

I use .270 WSM new cases of the Winchester brand which I neck them down using a 6.5/300WSM two-die set from Lee.

The bolt closed smoothly on the loaded cartridges but I found it was very hard to lift even with the starting load I was using that consisted of 63gr of TUBAL 8000, a slow burning powder in the H4831-MRP range, for 3,330fps. Also, it is very difficult to close the bolt on a fired cartridge.

The first thing I checked was to slide a bullet into the fired case neck and it would not.

Maybe the reamer used to cut the chamber is too tight, or maybe the neck thickens too much when it is necked down to the smaller caliber, or maybe a combination of both.

I do not want to get into the hazzles of outside neck turning and would like to try reaming the necks. I understand that neck reamers are normally used on fired cases, but I do not feel safe firing any more, and would rather ream new unfired .270WSM cases before necking them down.

I need a special size neck reamer that I will order from Forster that will ream the neck of a new unfired .270 WSM Winchester case but I am not sure what special diameter reamer I should order.

Does anyone have a similar experience or that can give some advise.

Thanks you and best regards,

Montero

Hi, assuming that the chamber has been cut correctly, I fear that the collet thickness is the culprit; the fact that you couldn't insert a bullet in a fired case neck is a strong pointer. I've checked with Quickload 3.3 and the neck diameter with a seated bullet should be 7.64 mm. Of course, it's only a guess.

thank you, Wildoar.

i am not sure what the "collet thickness" is, though...

Montero

Collet thickness means.....the thickness of the collet neck (sorry!); I had a similar problem 20 years ago, transforming some .270 Win. brass into 308 Win. At the end, the collet neck was so thick that I had to ream the interior and then anneal. I was younger and I had more time to waste. Sorry, but my English doesn't allow me to be more precise or clear.

Montero-

I personally load the .264/6.5 WSM and I learned and re-learned alot about reloading as a result and I have been handloading for almost thirty years.

The most likely culprit is that your case necks are too thick in combination with the chamber of your rifle. I picked up some Winchester, as well as Federal Brass last year in .270 WSM for use in my 6.5 WSM and I measured the wall thickness of the necks and they measured right at .018 inches. That translates to your chamber needing to be .299 to .300 inches for the outside diameter of your cartridges. Therefore, you may have to "turn" the necks of your cases from either outside turning or inside reaming.

The other posibility could be rate of twist and that your load is just pressuring up. I am loading 61 grains of Reloader 22 for 140 grain bullets. The rate of twist in my rifle is 1 turn in 8 inches. I can load up to 62 grains of Reloader 22 but, extraction starts to get sticky. The point that I am trying to make is don't assume that what worked in your .270 WSM is automatically going to work in your 6.5 WSM. They are different enough where things could fool you.

Good luck!!!

1. Measure the neck O.D. of a fired round.
2. Measure the neck O.D. of a loaded, unfired round.

The difference between 2. and 1. indicates the clearance between the cartridge neck and the chamber. If clearance is less than 0.003", there may be interference, giving pressure indications.

If you have adequate chamber clearance, there may not be a problem with the neck diameter. You should check your chamber's length to be sure the brass is not too long; 0.010" minimum clearance is a prudent figure. Sinclair sells a simple gauge that works with a shortened case to make the measurement simple: Item #G-264 (6.5mm) that sells for $6.75USD.

3. Measure the neck O.D. on a sized case.
4. Find the neck wall thickness and double it.
5. Subtract the product of 4. from 5. This will give you the neck I.D.

These dimensions will give you an idea of how much brass you want to remove with the reamer and its dimension.

You can ream the brass before reducing the neck size, but the amount of brass to be removed cannot be directly determined.

If you call and order your reamer from Sinclair, they will be able to advise you on the size. E-mail should work also.

1-800-717-8211 International phone no.: 260-493-1858
Phone hours are 8:00AM to 7:00PM EDT

www.sinclairintl.com
support@sinclairintl.com
FAX: 260-493-2530

If you want to avoid dicking with your brass, you can also have the neck of your chamber opened up with a neck reamer. Now you know what the neck diameter of a loaded round measures, you'll need that plus .003-.004" for safe bullet release (.002 in a target rifle - but for a hunting rifle, a bit more is probably an advantage).

You can order a neck reamer from Pacific Tools & Gauge if your smith does not have one handy.

- mike

quote:

Originally posted by Winchester 69:
If you call and order your reamer from Sinclair, they will be able to advise you on the size. E-mail should work also.

The Sinclair catalog indicates that custom reamers need to be ordered from Forster directly. Hope this hasn't been an inconvenience for you. An e-mail may still prove beneficial if you don't mention the brand.

We still haven't determined the exact nature of your problem. Sizing down from .277 to .264 doesn't generate a lot of excess brass thickness, but you're working with a custom chambering. The sizing process can generate excessive length for a custom chamber, although the symptoms don't suggest that it is the problem. Once we've determined that the neck thickness needs reducing and by how much, then determining reamer size can be approached.

The standard reamers for working fired brass are sized approximately 0.003" over bullet size, creating that amount of chamber clearance in the sized and loaded cartridge. With a custom reamer, you can achieve any clearance you want, but the method will be different for sized brass. Sizing with a button expander, outside turning is more accommodating of different brass thicknesses. Using a bushing sizer, a single reamer will achieve the same result. In the end, you are adjusting your neck wall thickness to fit the chamber.

I've tried measuring outside diameters of loaded and fired cartridges but I am not proficient with the use of the micrometer and I get erratic readings.

I have painted the neck of a loaded cartridge and chambered it and itcomes out with no markings. Conclusion: there is some clearence.

I have tried to slide a bullet into a fired case and it is not possible to do with your fingers. Conclusion: there is not enough clearence.

It can only be for two reasons, either the chamber neck is too tight or the case nech is too thick (or a combination of both).

I picked up a few new Winchester .270WSM cases and, to my surprise, the would hold (very lightly, but the would nevertheless hold it) a .264" bullet. Conclusion: the inside diameter is too small.

An this can only be for two reasons, either the outside diameter is too small and the neck thickness is right, or the outside diameter is correct and the neck is too thick (or a combination of both).

But the I go and pick up new Winchester 270WSM cases from another batch and the same .264 bullets that I tried with before slide into them much more freely, to the point that the neck will not hold them and they fall inside the case. I measure the outside diameter of these cases and I would say they measure the same as the other ones. I am not positive on this since my use of the micrometer is far from perfect.

I will fire a couple of them this coming weekend to see what happens. My guess is that their necks will still need some reaming but nos as much as the ones from the original batch.

I have contacted both Sinclair and Forster and I am waiting for their advise of the size of the neck reamer I need. A reamer to be used on a new unfired .270WSM case. Assuming a correct inside diameter of .273 and assuming some thickening on the necking down process, my guess would be use a .283 reamer, but we shall see what they say, and what happens this weekend.

montero

What's interesting is the industry's approach to alleviating the tight-chamber problem with their stock reamers. The tools are designed to provide minimal chamber clearance where it does not presently exist. The first step is prepping the brass: firing it in the too-tight chamber. Isn't this what the present discussion is attempting to avoid? The standard reamer does provide an elegant result, but how dubious is the means?

Wildboar, you hit the head of the nail when you said:

quote:

Originally posted by wildboar:
... assuming that the chamber has been cut correctly...

I definetely had a problem with the thickness of the neck of the sized down .270WSM cases. I have solved it by neck turning them before sizing them down.

But yesterday, before ever firing the rifle again, I decided to check the headspace and alas! the bolt would close on the no-go gauge!

In my opinion, with a too deeply cut chamber, the brass expands to a point close enough to its elasticuty limit where it does not bounce back. And that is where I believe my problems come from. Opening the bolt is difficult, as is closing it on a fired case.

Now, the rifle is back to the smith's shop, where the barrel will be screwed in one full turn and the chamber re-cut.

Thanks everybody for you opinions.

To be continued!

Montero

NB: wildboar, you have a private message