Reloading 270 win and 7mm

[Crimper]

Hi guys, been reloading 44 mags and 45/70 for a while now. Both with good crimp for leverguns but here is my question, I am about to start loading 270 and 7mm rem mag. Should I crimp these at all? 270 win will be used in a tikka t3. 7mm rem mag in a browning a-bolt. Will be using jacketed bullets in these rounds

 

[Cleftwynd]

I have never crimped the 270, or the 7mm STW. Haven't had a need to, just make sure you have enough neck tension and that there is no lube inside the brass.

 

[HIGHRPM]

No, I wouldn't or have crimper for either of those. Like mentioned neck tension is all you really need. Only really comes into play if you are reloading for a semi auto, then you would crimp.

 

[Scott_N]

I wouldn't crimp either rounds either.

 

[OldDude]

In a bolt action, with a suitable set of dies, you should be alright without crimping. For a semi-auto, I would crimp (and hove crimped), if the bullet had a cannelure.

 

[Crimper]

Thanks for your input guys I will be going the no crimp route and see how that works. Will be using rcbs dies.

 

[Boomer]

While crimping might not be "necessary," uniform bullet pull weight is one of the hall marks of accuracy, and something that is controllable by the handloader. Various ways to ensure uniform bullet pull weight is to: seat the bullet to contact with the lands, anneal your necks every second or third loading, or you can apply a light crimp. The down side of seating to the lands is that you will encounter pressure signs sooner than you would with a jump, and your OAL might be too long to cycle through the magazine. The downside of annealing is the time involved and the difficulty in getting uniform results. Applying a light crimp to each round simplifies uniformity, and takes little time although it is best done as a separate step from bullet seating. The more uniform you case length and seating depth, the better your results will be.

Your best course of action is to load a test batch of rounds crimped and another uncrimped. Don't fudge the results by loading the rounds differently for crimping, simply load everything the same, then randomly select the rounds from those loaded and crimp them. Shoot them on two different targets and see for yourself if there is any benefit to crimping. If not, you know how to continue, but if there's an improvement from crimping that you can measure, carry on. I only crimp bullets that have a cannelure or crimping groove, but I crimp when I can because I believe that it makes my ammo just a bit better.

 

[Crimper]

Thanks Boomer that is exactly what I was thinking when I asked the question.