Hello all-

I have a new Maynard No. 16 in my quiver. It was sold as a .25 Stevens rimfire, but proved to have been re-chambered for .25-20 WCF. 

I'm trying to estimate what weight bullet will be compatible with the barrel's twist rate of 1-18". I'm thinking the 65 grain bullets some have used for the .25 Stevens should work, but I don't find many options available in a flat base configuration. I am wondering if a 50-grain, flat base bullet from a .25 ACP mold might be a better bet. 

Any thoughts? I appreciate your suggestions!

Depends on the bullet, but will probably max out around 70 grains on a good day.

Check bore size and make sure it’s .257 or so, 25 acp bullets will be .251.

The Stevens rimfire twist is 17, so you might have another handicap to finding a good bullet. I’d be looking under 65 grains.

Hers a bullet that shoots quite well in my 25 rimfires. Lyman also had a couple 60-65 grain Moulds that you should look out for.

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frnkeore wrote on Aug 9^th, 2025 at 1:22pm:


I haven't slugged it yet, but will. The only .25 mold I have on hand is an old Ideal loading tool for .25-20 SS. I presume it will be too heavy to stabilize, but perhaps I will just try a few and see what results. 

.25 ACP is .251"? Well, I made a foolish presumption! Sadly, not the first time I have been guilty of this. 

Thanks for the help gents!

On the advice of a friend and contributor here, I ordered an NOE 260-63 plain base mold. Looks like a good little bullet, and I’m anxious to cast some and give them a trial. 

The Maynard these will be used in has a few mechanical issues to be fixed, so I will have plenty to do while I’m waiting for the new mold to arrive.