Gyroscopic Investing

Is my thinking incorrect? If I buy 30 year treasuries - does that mean that I am committed to PP for 30 years?  I have a hard time committing to a 30 year strategy. Plus, I  have my own personal opinion about the risk of the 30 year - including a selected default mechanism, ie the Treasury defaulting on the FED debt. Call me crazy but that is how I feel and I can't shake it. (Who would have thought the FED would become the largest purchaser of US obligations?) 
That said, it appears that I can I buy twice as many 10 years and get close to the volatility of the 30year? Looking at a long term chart comparing TLT to IEF, it appears that I can match the volatility with  2x IEF - (at least using those two proxies as comparison). To me that would be a safer alternative, because of the shorter time frame but maybe I am missing something?

You can sell the bonds at any time and are certainly not locked in to the PP for 30 years.

You're actually supposed to sell those bonds after ten years, b/c 20 years is the minimum duration to get that desired volatility.
Sell your bonds when they have 20 years until maturity and buy new 30-year bonds.

As for trying to increase volatility with more treasuries that are merely 10-year notes, I don't think it works that way.
What if you bought tons of t-bills? You'd have a lot of something, but not much volatility.

MangoMan wrote: Actually, Melveyr has shown that you can swap out the 25% cash and 25% LTT for 50% 10 year treasuries. So yes, if you dump the cash allocation as well, you can essentially have a portfolio that is very close to 4x25 that is 25/25/50  stock/gold/10 yr treasuries.

Returns over the long run were similar.  However, a barbell reacts different than a bullet strategy in changing rates in the sort term.  I like the 25 and 25 because barbell makes a rate transition a little less physiologically painful.